diff --git a/libraries/Fletcher/Fletcher.cpp b/libraries/Fletcher/Fletcher.cpp
index 088a7145..4e99381f 100644
--- a/libraries/Fletcher/Fletcher.cpp
+++ b/libraries/Fletcher/Fletcher.cpp
@@ -1,7 +1,7 @@
 //
 //    FILE: Fletcher.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.4
+// VERSION: 0.1.5
 //    DATE: 2022-01-25
 // PURPOSE: Arduino Library for calculating Fletcher's checksum
 //     URL: https://github.com/RobTillaart/Fletcher
@@ -15,6 +15,9 @@
 //  0.1.4   2022-09-08   performance optimization (Kudos to Daniel Mohr).
 //                       affects SAMD, ESP32 and ESP8266
 //                       fix FLETCHER_LIB_VERSION
+//  0.1.5   2022-09-08   roll back the optimizations in the standalone functions
+//                       conflict with loop optimization already in.
+//                       update ketwords.txt
 
 
 #include "Fletcher.h"
@@ -38,10 +41,10 @@ uint16_t fletcher16(uint8_t *data, uint16_t length)
       s2 += s1;
     }
     s1 %= FLETCHER_16;
-    //  does not work due to the above "32-bit" loop.
-    // s1 = (s1 & 255) + (s1 >> 8);   
+    //  this optimization does not work due to the above "32-bit" loop.
+    //  for all three functions.
+    //  s1 = (s1 & 255) + (s1 >> 8);   
     s2 %= FLETCHER_16;
-    // s2 = (s2 & 255) + (s2 >> 8);
   }
   return (s2 << 8) | s1;
 }
@@ -59,11 +62,8 @@ uint32_t fletcher32(uint16_t *data, uint16_t length)
       s1 += data[i++];
       s2 += s1;
     }
-    // s1 %= FLETCHER_32;
-    s1 = (s1 & 65535UL) + (s1 >> 16);
-    
-    // s2 %= FLETCHER_32;
-    s2 = (s2 & 65535UL) + (s2 >> 16);
+    s1 %= FLETCHER_32;
+    s2 %= FLETCHER_32;
   }
   return (s2 << 16) | s1;
 }
@@ -81,10 +81,8 @@ uint64_t fletcher64(uint32_t *data, uint16_t length)
       s1 += data[i++];
       s2 += s1;
     }
-    // s1 %= FLETCHER_64;
-    s1 = (s1 & ((((uint64_t) 1) << 32) - 1)) + (s1 >> 32);
-    // s2 %= FLETCHER_64;
-    s2 = (s2 & ((((uint64_t) 1) << 32) - 1)) + (s2 >> 32);
+    s1 %= FLETCHER_64;
+    s2 %= FLETCHER_64;
   }
   return (s2 << 32) | s1;
 }
diff --git a/libraries/Fletcher/Fletcher.h b/libraries/Fletcher/Fletcher.h
index 9e6c972d..a9588124 100644
--- a/libraries/Fletcher/Fletcher.h
+++ b/libraries/Fletcher/Fletcher.h
@@ -2,7 +2,7 @@
 //
 //    FILE: Fletcher.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.4
+// VERSION: 0.1.5
 //    DATE: 2022-01-25
 // PURPOSE: Arduino Library for calculating Fletcher's checksum
 //     URL: https://github.com/RobTillaart/Fletcher
@@ -12,7 +12,7 @@
 #include "Arduino.h"
 
 
-#define FLETCHER_LIB_VERSION              (F("0.1.4"))
+#define FLETCHER_LIB_VERSION              (F("0.1.5"))
 
 #define FLETCHER_16                       255
 #define FLETCHER_32                       65535UL
diff --git a/libraries/Fletcher/examples/Fletcher_random_stream_performance/Fletcher_random_stream_performance.ino b/libraries/Fletcher/examples/Fletcher_random_stream_performance/Fletcher_random_stream_performance.ino
index 87472c82..724e0033 100644
--- a/libraries/Fletcher/examples/Fletcher_random_stream_performance/Fletcher_random_stream_performance.ino
+++ b/libraries/Fletcher/examples/Fletcher_random_stream_performance/Fletcher_random_stream_performance.ino
@@ -1,6 +1,6 @@
 /*
   Author: Daniel Mohr
-  Date: 2022-09-07
+  Date: 2022-09-08
   Purpose: shows stream performance
 */
 #include "Arduino.h"
@@ -9,6 +9,7 @@
 #include <Fletcher16.h>
 #include <Fletcher32.h>
 #include <Fletcher64.h>
+#include <Fletcher.h>
 
 #ifdef ARDUINO_ARCH_AVR
 #define MAX_LEN 1024
@@ -18,6 +19,42 @@
 
 #define DO_N 23
 
+uint32_t myfletcher16(uint8_t *data, const uint16_t length)
+{
+  uint16_t s1 = 0;
+  uint16_t s2 = 0;
+  for (uint16_t i = 0; i < length; i++)
+  {
+    s1 = (s1 + data[i]) % ((((uint16_t) 1) << 8) - 1);
+    s2 = (s2 + s1) % ((((uint16_t) 1) << 8) - 1);
+  }
+  return (s2 << 8) | s1;
+}
+
+uint32_t myfletcher32(uint16_t *data, const uint16_t length)
+{
+  uint32_t s1 = 0;
+  uint32_t s2 = 0;
+  for (uint16_t i = 0; i < length; i++)
+  {
+    s1 = (s1 + data[i]) % ((((uint32_t) 1) << 16) - 1);
+    s2 = (s2 + s1) % ((((uint32_t) 1) << 16) - 1);
+  }
+  return (s2 << 16) | s1;
+}
+
+uint64_t myfletcher64(uint32_t *data, const uint16_t length)
+{
+  uint64_t s1 = 0;
+  uint64_t s2 = 0;
+  for (uint16_t i = 0; i < length; i++)
+  {
+    s1 = (s1 + data[i]) % ((((uint64_t) 1) << 32) - 1);
+    s2 = (s2 + s1) % ((((uint64_t) 1) << 32) - 1);
+  }
+  return (s2 << 32) | s1;
+}
+
 void setup()
 {
   Serial.begin(115200);
@@ -52,7 +89,12 @@ void test_fletcher16() {
     totaltime += t1 - t0;
   }
   Serial.print("Checksum: ");
-  Serial.println(checksum);
+  Serial.print(checksum);
+  Serial.print(" ( != ");
+  Serial.print(fletcher16(values, max_len));
+  Serial.print(" != ");
+  Serial.print(myfletcher16(values, max_len));
+  Serial.println(" )");
   Serial.print("Created checksum: ");
   Serial.print(1024.0 * totaltime / float(DO_N * MAX_LEN));
   Serial.println(" us/kByte.");
@@ -86,7 +128,12 @@ void test_fletcher32() {
     totaltime += t1 - t0;
   }
   Serial.print("Checksum: ");
-  Serial.println(checksum);
+  Serial.print(checksum);
+  Serial.print(" ( != ");
+  Serial.print(fletcher32(values, max_len));
+  Serial.print(" != ");
+  Serial.print(myfletcher32(values, max_len));
+  Serial.println(" )");
   Serial.print("Created checksum: ");
   Serial.print(1024.0 * totaltime / float(DO_N * MAX_LEN));
   Serial.println(" us/kByte.");
@@ -120,7 +167,12 @@ void test_fletcher64() {
     totaltime += t1 - t0;
   }
   Serial.print("Checksum: ");
-  Serial.println(print64(checksum));
+  Serial.print(print64(checksum));
+  Serial.print(" ( != ");
+  Serial.print(print64(fletcher64(values, max_len)));
+  Serial.print(" != ");
+  Serial.print(print64(myfletcher64(values, max_len)));
+  Serial.println(" )");
   Serial.print("Created checksum: ");
   Serial.print(1024.0 * totaltime / float(DO_N * MAX_LEN));
   Serial.println(" us/kByte.");
@@ -131,10 +183,10 @@ void loop() {
   Serial.print(MAX_LEN);
   Serial.println(" elements for Fletcher16");
   Serial.print("Using list of ");
-  Serial.print(MAX_LEN/2);
+  Serial.print(MAX_LEN / 2);
   Serial.println(" elements for Fletcher32");
   Serial.print("Using list of ");
-  Serial.print(MAX_LEN/4);
+  Serial.print(MAX_LEN / 4);
   Serial.println(" elements for Fletcher64");
   Serial.println("");
   test_fletcher16();
diff --git a/libraries/Fletcher/keywords.txt b/libraries/Fletcher/keywords.txt
index 5265eb25..9ee16661 100644
--- a/libraries/Fletcher/keywords.txt
+++ b/libraries/Fletcher/keywords.txt
@@ -11,6 +11,11 @@ fletcher16	KEYWORD2
 fletcher32	KEYWORD2
 fletcher64	KEYWORD2
 
+begin	KEYWORD2
+add	KEYWORD2
+getFletcher	KEYWORD2
+count	KEYWORD2
+
 
 # Constants (LITERAL1)
 FLETCHER_LIB_VERSION	LITERAL1
diff --git a/libraries/Fletcher/library.json b/libraries/Fletcher/library.json
index 941e89d2..6bdf6e8b 100644
--- a/libraries/Fletcher/library.json
+++ b/libraries/Fletcher/library.json
@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/Fletcher.git"
   },
-  "version": "0.1.4",
+  "version": "0.1.5",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",
diff --git a/libraries/Fletcher/library.properties b/libraries/Fletcher/library.properties
index c0fe06ce..9014ba74 100644
--- a/libraries/Fletcher/library.properties
+++ b/libraries/Fletcher/library.properties
@@ -1,5 +1,5 @@
 name=Fletcher
-version=0.1.4
+version=0.1.5
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence="Arduino Library for calculating Fletcher's checksum.