Mistake of Fact safe harbor match after one year

[kwalified]

A large plan has a few participants that received a safe harbor match and were not eligible. For example a match was issued starting with the Jan 2012 payroll. The error was discovered past the one year Mistake of Fact rules under 403©(2)(A). So how should the error be corrected?

[BG5150]

Move the money + earnings to the suspense account and use to offset a future SH match.