Ask the lender or broker for a comparison of the up-front costs, principal, rate, and payments with and without this rate trade-off.
Mortgage can last a lifetime and that extra 1% can add up to literally thousands of dollars over the years. I have friends that are in their 70s and still paying off their home loans. It'll pay off in the long run to make sure you find the best deal possible. Don't let poor credit stop you from refinancing your home.
You can ask for a copy of your settlement cost papers (the HUD-1 form) one day in advance of your loan closing. This will give you a chance to review the documents and verify the terms.
If you are able to get a lower rate that what you currently have, you can save tens of thousands of dollars over the life of your loan. Also, most lenders don't charge as many fees to refinance a mortgage and depending on how much equity you have in your home you may be able to roll the closing costs into your new loan, still have a lower balance than your original loan, a lower rate, and a lower payment.