Stopping discretionary match mid-year revisited

[John A]

How can an employer stop a discretionary match mid-year in the following situation:

Employer has been putting match in on a payroll period basis.

Plan document implies that the match will be determined based on annual deferral amounts.

An employee that had deferrals has terminated employment.

The plan document is silent about true-ups.

The employer is not willing to freeze participant's abilities to make deferrals.

Is the employer stuck with contributing at least the match rate of the employee that terminated to all other employees based on their deferrals for the rest of the year? If so, cite or support?

Could the employer amend the plan to a short plan year, and immediately start a new plan year?

The employer claims to have stopped the match mid-year several years ago without any problem - has there been any change in this area over the last few years?

Issues (some also mentioned in above threads):

1. Following terms of the plan document

2. Discriminatory rate of match [1.401(m)-1(a)(2)]

3. 411(d)(6) - had participants accrued right to a match of at least highest rate made so far?

4. Definitely determinable formula [1.401-1]