Erroneous exclusion of partipant to plan correction calculations

New user.  Appreciate the forum.  

EPCRS 2021-30 provides that for a 401(k) plan that does not satisfy § 401(k)(3) by applying the safe harbor contribution requirements of § 401(k)(12) or 401(k)(13), "...missed deferrals are determined by multiplying the actual deferral percentage for the year of exclusion..."  

The plan did not do a nondiscrim. test, and I am wondering: can we use a different calculation to correct this issue?  

Grammar edit

Why don't you just do the test?