ACP Calculation for Discretionary Match stopped mid year

If the employer chose to stop their discretionary match mid year, would the compensation for determining ACP testing also only be for the period of time the match occurred during the year or is full Plan Year compensation always used?  

I seem to be having the hardest time being able to confirm this.  

Compensation for the ACP test must be 414(s) compensation. If you are using anything other than a safe harbor definition of compensation, such definition has to be reasonable, and it has to satisfy the compensation ratio test. I have no idea whether a definition that excludes all pay after a given date would be considered "reasonable."

3 hours ago, ERISAGal said:

If the employer chose to stop their discretionary match mid year, would the compensation for determining ACP testing also only be for the period of time the match occurred during the year or is full Plan Year compensation always used?  

I seem to be having the hardest time being able to confirm this.  

You can't confirm it because you are looking for something that is not there.  The numbers are done for the plan year; doesn't matter when the discretionary match was made.