If I am understanding your time line.
GFE provided quoting a rate of 3.35%. My questions is, in the "important dates field", how long did you say that rate (3.35%) is good for in question one? If it is like most banks it is only good the date of the GFE. And if they locked their rate after that date, then they get that rate (3.5%).
So, my second question is, how does the consumer know their rate is locked? Did you have them sign a Rate Lock disclosure? If yes, then that is the rate they get.
The only problem I see is, any fees that may have changed when you locked their rate, those are now items you will need to cure (if they were higher).
I hope I explained this right?
_________________________
I'm only responsible for what I say, not for what you understand.