If you want to create a 5-minute, 10-minute, 15-minute, etc. Service and you only see 30-minute, 1hr, 1:30 durations, or you want your employee to work from 09:15 - 10:20 all you need to do is change the Default Time Slot step in Amelia's General Settings:
The Time Slot Step applies to all times in Amelia (Service durations, buffer times, employee's working hours and breaks), and if you want to shorten the duration, you need to change the Default Time Slot step.
For example, if you want a 45-minute service, a 1-hour long service, and a 10-minute long service, you need to set the default time slot step to "5 minutes" because all times in Amelia need to be dividable by the default time slot step (you can add 15-minute time slot step, but in that case, you won't be able to make a 10-minute long service).