Safe Harbor and Plan Sponsor Acquistion

We have a client who requested a plan termination due to acquisition effective December 18, 2017.  Plan Year end is 9/30 and is a safe harbor plan.  Termination paperwork has been signed.   We informed the client that the plan can still be safe harbor for a short final plan year if the plan termination is in connection with a 410(b)(6)(C ) transaction. 

Yesterday we hear from the client that the acquisition date has been pushed back to March 2018 due to insurance issues and that employees will continue to be paid by the current plan sponsor until then.  Our concern is that the termination date is earlier than the acquisition date and that the plan is now subject to ADP Testing and Top Heavy.  What are your thoughts regarding this?  Do we need to change the termination date of the plan to March in order to satisfy the acquisition exception? 

I don't see anything in 1.401(k)-3(e)(4) that prevents the termination date from being more than a certain amount of time before the transaction date.  It just specifies what applies if the termination is in connection with a 410(b)(6)(C) transaction.  So, facts and circumstances?

There was a question at the 2012 ASPPA annual conference DC Q&A session dealing with voiding a mid-year amendment to suspend the SH contribution.  You probably barely have time to do so and fit in the situation mentioned in the question that received informal blessing. 

I would be inclined to void the termination amendment and re-adopt closer to the transaction date for a couple of reasons.  First, what happens if the transaction doesn't happen (or if it gets delayed further)?  Second, I would prefer to have the participants be able to defer as continuously as possible during the transition to the acquiring firm.

Anyone else have an opinion?

I would delay the termination date until closer to the transaction. I'm not aware of a maximum timeframe either, but 3-4 months strikes me as a little long. Also, FYI, I constantly have recordkeepers (providing plan docs) insist that sponsors need to provide 30 days' advance notice to terminate the SH plan, even in connection with a transaction, which is just flat-out wrong. So the misconception is rampant.