Should I refinance this property?

[Paul Scammacca]

Property current mortgage 72,300 5/1 ARM 5.5 percent opened 2/1/20

Refinance: Around total 77,000 cc/fees/prepays payment near 545 30 year fixed

Current payment with adjusted tax will be about 640 per month on the 5/1 arm 

So i would save about 100 per month but lose a few years in making up costs........................thoughts??  Also, they ran a 15 year and it was about 730 per month, property rents for 1000 per month, not sure what to do. Thanks, P.