Some regulations kick in because of loan purpose
Some because of collateral
Some by type of borrower.
There is not one regulation which addresses which regs are in effect for loans originated in the residential, consumer, commercial, or whatever loan department. That is a bank choice! What matters per the regulation are the above 3.
The bank can have a consumer PURPOSE loan in the commercial department, and it is still a consumer purpose loan with all the disclosures and nuances. Vice versa.
Integrity. With it, nothing else matters. Without it, nothing else matters.