Filing under Delinquent Filers VCP

An 8/31/2016 5500-SF was never filed.   Client received a letter from IRS letting them know it was never received. .   They are going to file it today, under DFVCP.    The letter gives them the option of filing under DFVCP, and it asks for the date applied.    What date would they put in there when replying?   The date the 5500 was actually filed? 

Also, do they pay the fee right away, or do they wait for a reply from the DOL? 

Thank you,  this is the first time for filing under DFVCP. 

They pay right away.  You can do that on the DOL website.

Is the date they file under DFVCP the date they file the 5500 or pay the fee? 

I think when you pay online you have to put the date it was filed in EFAST.  I believe it is triggered off the filing date which may be less than small plan or large plan filing fee if less than a certain number of days.  I always either file on behalf of the client or have them file electronically same day as payment.