Actually yes, that is what we're doing. We are (currently) making the equivalent of 1 extra mortgage payment a year, which should reduce the amount of interest

Actually yes, that is what we're doing. We are (currently) making the equivalent of 1 extra mortgage payment a year, which should reduce the amount of interest that is paid over the lifetime of the loan. That, coupled with the increased value of the house since we've bought it, would help us remove the PMI payment. Doing the Maths, paying the extra 10% down, wouldn't save us much over the length of the loan where PMI applies, so we opted to make an extra mortgage payment instead.