Process Validation run required for completed validation effort ( process change)

Hi Sir,
I have completed the whole validation activities (IOQ and PV run) for all of the PCBA. For PV run, we ran a total of 5 batches to complete each model. The justification of 5 runs is based on the AQL switching rules. Now, there was a change where customer requested to move the non-ROHS PCBA to ROHS PCBA. Questions are:

  1. How do i determine the number of batches required to complete the PV effort. I know the 3 batches rule is no longer valid.
  2. I’m thinking about having an impact assessemnt that will determine the batch size required but i do not have a guideline for this.

I would appreciate if someone can shed some light here.