The story of MDIS is that it responds to farm market prices, 1998-2010.  Like the NFFC bill, this is backed by econometric studies showing how subsidies can be eliminated (or in this case, greatly reduced,) without devastating family farmers. 1998-2005 we had the lowest farm commodity prices in history (ie. 6+ of 10 lowest, 2010 $.)  Then we had some prices 3x higher (but not near record levels, if adjusted for inflation). 

This program is set up to make agribusiness pay higher prices during the low period, and also protect consumers, livestock interests, processors, etc. from the much higher prices.  It uses a new kind of price floors and ceilings, backed by supply management.