The $60 increase is based off of someone who claims a homestead exemption (20%) on a $215,000 home. That value is the average home value on the island.
$215,000 x .80 = $172,000/$100 = $1720 x .035 = $60.20
You can do the same math to come up with the impact to you. Simply take the value of your home and multiply it by .80 if you take a homestead exemption. Once you have that value you will divide that amount by $100 and multiply that number by .035.