diff --git a/samples/sim65/timer_example.c b/samples/sim65/timer_example.c
index 0675979b1..8262bdff8 100644
--- a/samples/sim65/timer_example.c
+++ b/samples/sim65/timer_example.c
@@ -41,7 +41,6 @@
  */
 
 #include <stdio.h>
-#include <stdlib.h>
 #include <sim65.h>
 
 static uint32_t timestamp(void)
@@ -67,9 +66,9 @@ int main(void)
 {
     unsigned max_term;
     unsigned long result;
-    uint32_t t1, t2, overhead, duration;
-    int32_t d0, d1;
-    int32_t  predicted_duration;
+    uint32_t t1, t2, overhead;
+    int32_t d0, d1, duration;
+    int32_t predicted_duration;
 
     /* Calibration measurement of zero clock cycles, to determine the overhead. */
 
@@ -101,9 +100,11 @@ int main(void)
     max_term = 10000;
     predicted_duration = d0 + max_term * (d1 - d0);
 
-    printf("predicted duration for max_term = %u: %lu\n", max_term, predicted_duration);
+    printf("predicted duration for max_term = %u: %ld\n", max_term, predicted_duration);
 
-    /* Do the actual measurement for max_term = 10000. */
+    /* Do the actual measurement for max_term = 10000.
+     *  Note: equality between the prediction and the measurement is only achieved if we compile with -O.
+     */
 
     t1 = timestamp();
     result = calc_sum_terms(max_term);
@@ -111,7 +112,6 @@ int main(void)
     duration = (t2 - t1) - overhead;
     printf("max_term = %u -> result = %lu; duration = %ld\n", max_term, result, duration);
 
-    /* Report success or failure. */
 
-    return (duration == predicted_duration) ? EXIT_SUCCESS : EXIT_FAILURE;
+    return 0;
 }