Mortgages that meet the definition would be presumed to meet the standards regarding the ability of the borrower to repay. These rules are important because violation of the standards could subject lenders to penalties and, in some cases, impede their ability to collect on defaulted mortgages.
If in recent years the frequency of price changes has increased, we would move from a flatter to a steeper short-run Phillips curve. On the surface, moving from the blue to red dot, it again looks like an essentially vertical Phillips curve, but just as in the first story, the data are showing us points on different Phillips curves.