A contract is a contract. Once all parties have signed and it's set to close there is very little wiggle room. You always run the risk of seeing a more favorable rate after you close. Or, rates might also go up, ya just never know.
"Sort of" is such a harmless thing to say. "Sort of". It's just a filler. "Sort of" - It doesn't really mean anything. But after certain things, "sort of" means everything. Like after "I love you" or "You're going to live" or "It's a boy".