Fortunately, We have a spreadsheet for this.
@Boofinator 's advice above is spot on.
By paying an extra $200 a month until PMI is gone, you would lose out
($141,011) over the life of the loan.
By paying an extra $200 a month until the entire mortgage is gone, you would lose out
($237,014) over the life of the loan.
That is including inflation and still using an over-conservative 9.5% figure. Historically the S&P will do 10.5% to 11.5% with dividends reinvested, excluding inflation losses.
6% is WAY conservative.
Also, I did a 15% marginal total tax rate (state and federal, combined). Feel free to adjust it as needed.
I would say don't pay extra in to kill the PMI, instead research your options to remove PMI via appraisal and home-improvement. Be patient, and kill the PMI another way.
(FYI - PMI of 0.3% is a fantastic PMI rate. It seems most are around 1% of cost of loan from what I've seen on here. )