I believe pass interference penalties should work the same way as far as penalty yards go, regardless if it is offensive or defensive. Something needs to be established here for equality.
1. No pass interference call, no matter how deep down the field whether it be from the offense or defense can be a penalty of more than 15 yards.
OR
2. We can keep things the same, but apply it to offense as well. Let's say we have offensive pass interference 40 yards down the field, I think then it should be a 40 yard penalty on the offense. So, if it was originally 1st and 10now it is 1st and 50 for a 1st down.