Batch Enrollments with New Plan Rates

We're using batch enrollment to apply new health care rates for the new fiscal year.  Here's my question - can you do this ahead of time like now, end one enrollment period and have the new dba start with the new rates.  or does it have to be done after the last pay period and before the first payroll is processed.    In previous years they had the understanding that it had to be done after the last pay period and beginning the new pay period.

The testing looks like it works with the new rates, but I am not able to simulate the 2016 new pay period in our test environment with confidence that it does work.