I don't know if there have been more responses to this post from a few years ago or there have been new posts on this topic. But if a plan is frozen, overfunded, top heavy and not covered by PBGC it has to pass 401a26. If a plan had a formula before the freeze that gave some participants a de minimus benefit equivalent to 0.5% of pay, then even using the average accrual method, you would fail 401a26 at some point after the freeze. Maybe you get a technical pass the first year of the freeze if you test at the beginning of the year on the average accrual method. But after that you will fail if you accept the 0.5% as the minimum necessary.
Note that if a plan is not covered by PBGC and is UNDERFUNDED it still does not seem to get an automatic pass on 401a26.
It seems that frozen plans in some circumstances must be unfrozen?
Am I wrong in the above? Has anybody had an audit where this issue came up?