Your local government has a building code dept to inspect new dwellings to certify them.
It is FREE to visit this department
It is FREE for them to explain local building codes and make xerox copies to give to you.
When you have this copy flapping in hand you have the master document which over-rules comments and any contractor or "expert".
Further plan, whine, moan or celebrate, only after you have this document in hand and have read it.
This has to due with fire and liability insurance plus avoidance of code violations not budgets or personal opinion.