If we correctly understand our colleague David Friedman, an economist, anti-deficiency legislation does not function to prevent the aggravation of an economic downturn if the creditors who are deprived of the money could have made better use of the money than the debtors whose liability has been excused.  Thus, it may well be that neither rationale for 580b is sound.  See our earlier note in this case that questions the overvaluation rationale.  580b might be better explained simply as depression era welfare legislation for homeowners, but that does not explain its application to purchase money transactions involving commercial property.