Mortgage rates have ticked downward in April, despite the Iran War, a decline that gives nearly 3 million homeowners a chance to lower their monthly payments with a refinance, a Bankrate analysis shows. The average 30-year fixed mortgage , the most popular type of home loan, has dropped to 6.34%, down 12 basis points since the beginning of the month, according to the latest Bankrate estimates. Mortgage rates, which are primarily tied to the bond market, have steadily eased off their highs for the year as the U.S. and Iran pursue an end to the conflict and hopefully free up shipping lanes that supply 20% of the world’s oil.  A Bankrate analysis of lending data found about 2.7 million homeowners with a 30-year fixed mortgage could lower their payments by refinancing right now. And for every basis point – or one-hundredth of a percentage point – that the current rate drops, roughly 90,000 more homeowners would benefit from a refinance.…