My guess is it would turn on whether the delay had some real purpose. Absent that, it is an easy argument to call it constructive receipt as of the earlier date where payment could have occurred.
A genuine reason for the delay might be a valuation suit, or reasonable belief that insufficient tenders would occur for the deal to go through.
I used to like working stuff like this when I had a tax library on hand.
How amazing are the deeds of the LORD! All who delight in Him should ponder them. Ps 111:2