403(b) Plan missed match - lost earnings start date is when?

[Guest SuzieQNEC]

A 403(b) Plan has determined that it has not contributed enough match going back about 8 years (compensation was understated in the actual calculation). The plan and company's fiscal year is 6/30. Generally match was made on a payroll basis, but a true up was always done at the end of the year. They are planning to make up the difference now in match and then make up for lost earnings. When determining the start date for the calculation of lost earnings, would it start a full one year after the end of the plan year? Here's an example:

Plan year 7/1/00-6/30/01

Employer contribution deadline is 6/30/02

Lost Earnings would start being calculated on 6/30/02.