true-up for match that changed mid-year

[Guest cxs]

I am doing a true-up match calculation for a plan that changed the match formula mid-year. I have compensation, deferrals, and match for the first 8 months (old formula) and the next four months (new formula). What is the correct way to calculate the true-up for employees that exceeded the compensation limit of $205,000.00 in the first part of the year? For instance, an employee makes $400,000.00 in the first 8 months and contributes $7,000.00. He makes 400,000.00 in the next 4 months and contributes $5,000.00. Can I prorate the cap to $136,673.50 for the first 8 months and $68,326.50 for the next 4?

Or is it correct to prorate the two match formulas for all employees? This is difficult since the formula for the first 8 months was 50% up to the first 6% deferred, while for the next four it is 100% for the first 2% deferred, and 50% on the next 6% deferred.

Thank you.