Read back through what I posted please, it appears that you did not - or else just didn't read the dates correctly.
For example: If the shop was done on the 27th of December, by Marketforce's own website and rules-of-operation, I was to receive the check for that NO LATER than the 20th of this month. As it was last month's, it would have been a higher probability to have received it on the 16th. (The 15th was a Sunday.)
As you quoted, "no later than the 20th of each calendar month." That sir, would be considered a promise or a contractual agreement. Than again, as you asked afterward, the shops were/are all confirmed and the CPI verified.
I have tried to contact the help desk, have e-mailed them otherways, and have spoken to a (very rude) lady who ended up admitted that she didn't/"don't know" and hanging up on me before I could reply.
True, I have worked with Marketforce for about 4 years now; in three states; and this is the second time that they've done this. The other time was in NC and they had computer problems in processing the checks (what I was told at that time, but I got my check about three weeks late and that was all). So I'm glad that you haven't had any issues thus far.
As for the posts above.... I have a direct deposit on 1/12/2017.