I am taking over a plan that used projected unit credit as the funding method. The accrual method is years of participation with no limit on years. However the funding is over 10 years. The benefit is the 415 limit. My understanding is that this is an old method that is acceptable. Is this method an acceptable funding method?

Well, I am answering my own question and thought I would share. Rev Ruling 85-131 Says under the Law section , referring to Sec 1.412©(3)-1© determining a plan's normal cost and accrued liability for a particular plan year - "The allocation of projected benefits of the plan between past years and future years must be in proportion to the applicable rates of benefit accrual under the plan". And Notice 87-21 says that the change to Rev Ruling 85-131 due to changes requiring 10 years of participation for the dollar limitation, limits the accrual for a year to the 1/10 per year of participation 415 $ limit. But nothing appears to allow a plan to fund for accruals that have not yet been accrued. Therefore, unless anyone else has other information, I will assume that the prior actuary was in error.

Have these accruals been limited because of the application of the 415 limit 10 year proration? It seems that is not what you are saying, rather, the plan is funding over 10 years when the accruals are over, say for example 20 years. There are ways to argue about the former, but I don't think the latter situation can be debated as correct.