plus the FDA is concerned about safety, not about you getting 'cheap sugars instead of pricier sugars'.
I'd say its very true. Some brands of DME are known to be low attenuating (excessive unfermentable sugar) compared to others.
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10