No, it’s not a bug. This is documented in the user manual, it is in granularity of 5 seconds. We have to balance the granularity vs. range — some users wanted extra long station delay time. The firmware uses only 1 byte to store the station delay time (as with all other options too), so we need to make a tradeoff between the granularity and range. Does 3 seconds vs. 5 seconds make that much difference to you?