Retro Ben Ded Program Configuration

I am looking for best practices for setting up the PeopleSoft 9.1 Retro Ben Ded Program - i.e. to what level of detail do you need to go to when defining.

For example - we have:

Plan Type 10, Benefit Plan = HCP001, Coverage Code 1 and 4, Deduction Code = 703; Deductions Classes = After Tax, Non Taxable, Taxable QC

There are 8 Benefit Programs that all have health plan HCP001 and the same the coverage Codes, Deduction Code and Deduction classes

So, for configuration - can I just add Plan Type 10, Benefit Plan = HCP001 and nothing else?

If the fields are left blank - does retro pick up the coverage, deduction, classes from the Benefit Program?