Thom,
What's been posted is correct. The new MIP monthly premium is going to eat up the monthly savings. But there are a couple of other items to consider and it may be worth having a lender work up an actual quote.
1. when you refinance you're eligible to get a refund of a portion of your upfront funding fee. This would come close to covering all of the new upfront. Meaning you won't be adding to your current loan this time around for the upfront MIP.
2. If you're planning to stay in your home loan term the MIP will come off when you get to 80% of your loan to value (based on the original value). That would be a large savings. This usually happens around month 110 in a normal payment amortization.
3. If you sell in the future and rates are higher a buyer could assume your loan through FHA. That means you could have an advatage at 4% over another home that doesn't.
Lastly, if you can refinance and save anything on a monthly basis and have a low net time frame to recoup the costs of the refinance and the above benefits have value to your situation that I would move forward.