15+ PCM Unlock cost

I just have a couple of questions. Originally it was 250 plus credits to unlock the pcm. Then HPT changed it so that if you purchased credits at the same time as the pcm unlock, the unlock was free of charge. Is this still a thing, because I just added the unlock service and credits and my total didn't subtract the unlock. So I'm really confused as to the cost 550 or 300. Then if I get a new computer unlocked from HPT and mine is 900, do I still need to purchase 300 in credits for a total of 1200?

Thank You
Bad383TA

i think that was if you bought a new interface

the 3 that everyone loves

It was purchase six credits and a computer unlock at the same time, then the computer unlock would be removed from your bill. Now after some research, I see a few months back they changed things up, so you now have to also purchase a 3 interface at the same time.