Okay to change from current year, disaggregation in 1 year, to prior y

[John A]

Can a plan that has used permissive disaggregation and current year testing change in the next plan year to use prior year testing and not use permissive disaggregation?

I have been trying to understand Notice 98-1, and it appears to me that this is possible, although the disaggregation change would constiture a "plan coverage change." It appears to me that this would mean the plan could treat the disaggregated groups as the "prior year subgroups."

Has anyone done this before?