Incorrect Vesting Applied

[Guest lostinpensions]

We submitted a terminating plan for a favorable determination letter, and the IRS discovered that we did not apply the plan's vesting schedule appropriately for a short plan year that occured many years ago (resulting in underpayment of benefits for several employees). We have been asked to correct using the "contribution correction method" (Rev. Proc. 2003-44, Appendix B, Section 2.03(1)(a))

This particular section does not specifically say how to adjust for earnings. Does anyone have any suggestions on how to adjust for earnings? I am new at this.

Thanks for your help. Any input would be greatly appreciated.