They are from Chiliad and are the one's specifically to be used in conjunction with BedwardsRoy's roster set. The 2012 draft is actually posted by BedwardsRoy but uses Chiliad's work, then the 2013-2015 drafts are under Chiliad's name but make note in the description that they are optimized for use with Bedwardroy's rosters. The reason is that Bedwardroy's rosters have some very specific edits such as making all the isoloation tendencies zero and making other tendencies add up to 100 per "group." If a draft class isn't done in the same way, it would probably be fairly incompatible.
Hope that helps. I plan on continuing to do my Pistons dynasty as well, although probably simming almost all the games, atleast until the playoffs. Just kinda taking a break right now.