Need advice on creating a discrete manufacturing routing

 We are using JDE World version 7.3 cum 11.  I am trying to set up a discrete manufacturing routing of several steps that has 1 step that can be batched  (let's say, put into a dryer). The time for a batch of 1-10 items is 10 minutes (1 item takes 10 minutes or 10 items takes 10 minutes and I can have orders for any number of items), 11-20 would take 20 minutes.   Using the Time Basis code seems to divide the overall time by the number of items (1 hour per 10 items gives me a time of 6 minutes for 1 item, not the 1 hour for 1-10 items as I was hoping).