So I've tried the loophole for this window and last window and I'll share my experiences. BTW, I'm a TN candidate.
The first time I tried it I had passed FAR and AUD, had a NTS for REG, and was waiting for my BEC score. I waited until the day after the BEC scores had been released to NASBA and checked the OH "Re-exam Registration" link on the NASBA site. It gave me the "in process" message. I ended up passing BEC.
So the second time I tried it, I had passed FAR, AUD, and BEC and was waiting for my REG score. I log into the OH site the day after scores are released to NASBA, and it let's me register for REG and the sections I had passed are grayed out. And I ended up failing REG.
Also, the TN "Re-exam Registration" site now looks exactly like the OH "Re-exam Registration" site. The TN site would let me register for REG and the other sections were grayed out the day after scores were released to NASBA.
Back to studying for me....
TN Candidate
FAR - PASS, AUD - PASS
BEC - PASS, REG - DONE!!!!!!