Index: stamper/stamper.py
===================================================================
--- stamper/stamper.py	(revision 67)
+++ stamper/stamper.py	(revision 69)
@@ -284,4 +284,6 @@
                         # remove the seconds part from the string representation
                         tc_total = ':'.join(tc_total.split(':')[:-1])
+                        # ensure hours show double digits
+                        tc_total = tc_total.zfill(5)
                     customer_day_totals.append(tc+': '+tc_total)
                 print(', '.join(customer_day_totals))