In testing an alternative defintion of compensation, the regs (1.414(s)-1(d)(3)) say that the average inclusion percentage (AIP) for the HCEs may not exceed the AIP for the NHCEs by more that a de minimis amount.

Is there a "safe harbor" definition of de minimis? Is 4.57% (97.35 vs 92.78) de minimis?

Does anyone have experiance with the type of "facts relevent to whether the difference is de minimis" (from Item 8 of the 5300 Schedule Q Demo 9 instructions)?

I have seen 3% listed as a rough guidline, and a rough guidline at best.
so, I would say your 4.57 sounds high

There is no safe harbor and I agree that 4.57 sounds high. To me, if the employer is trying to favor NHCEs, then the alternative definition would fly. Otherwise, why even bother attempting to exclude certain items when there can only be a de minimis difference. It seems like a lot of effort for no gain.