Benefits setup for ESS for Open Enrollment

We are looking to add an additional deduction for certain plan options within our plans for this years open enrollment,  Normally I would create all new dba's and plans to use for Open Enrollment.  Does anyone know if there is an easier way to add this to our current plans without having to create all new ones for Open Enrollment? 

My concern is that we will be opening up OE for our employee in two weeks.  The effective date for ESS is 4/14/2018 for the first check in May.  If I do a batch enrollment to accomodate for the pay period till then, how will the system handle the new dba?  will it use the start date on the dba or will it use the effective date of batch enrollment.