So, let's say the units are sold at 80-120% of the moderate income levels.  Due to market demand (demand is outstripping supply), once these units are resold, they will revert to market price, so they' won't be 'affordable' or purchased at lower than market value to the second owner.  This is a double-edged sword, as it allows the initial buyer (who bought at a discount), to make a profit, and potentially afford to upgrade to a better home), but inhibits future buyers of the same property at an 'affordable' cost.  Let's say we make 100% of these units affordable.  Immigration will increase and/or emigration will decrease, as the cost of housing and therefore cost of living is lower.  I've been watching this debate here for more than 23 years!