Is there a formal definition for the term "Hybrid Plan"? Is a Floor-Offset arrangement a "Hybrid Plan"? Ever? Always? Never? Any opinions regarding the application of vesting requirements under PPA2006 to a Floor-Offset arrangement?

Thanks for your input.

Floor-offset discussions are a separate concern from hybrid "applicable plans" using cash balance formulas.
You could have one feature or the other or both or neither.

Floor-offset plans can only offset the vested portion of employer funds from a DC plan. If you have different vesting schedules for the two plans, the net benefit can be dramatically affected by their differing vesting rates.

If you have an applicable plan, then you cannot exceed 3 year cliff vesting for its benefits.

If you are offsetting a DC plan, the employee deferrals cannot be offset. I don't allow any plans I design to offset the employer matching funds either.