Niz, you are correct. Mashing the grain will convert the starches to sugar, steeping will only release the simple sugars. A caveat is that the more kilning the malts get the more enzymes are destroyed, these enzymes are used to covert the starch to sugar during mashing. This is what's referred to as the diastatic power or Lintner of the grain. Higher kilned malts have a lower diastatic power which is why they can't be mashed alone, there aren't enough enzymes to convert the starches.
http://beersmith.com/blog/2011/11/17/brewing-beer-with-dark-grains-steeping-versus-mashing/
Suggests that the higher kilned malts, eg. chocolate, will have some starches coverted and the rest mostly destroyed so thats why you can mash or steep. They definitely have had all their enzymes destroyed so they can't be mashed by themselves.
So I spose the question is, how much starch was left in the brown malt I got? The answer is...? I think I might ask the malsters!
http://beersmith.com/blog/2011/11/17/brewing-beer-with-dark-grains-steeping-versus-mashing/
Suggests that the higher kilned malts, eg. chocolate, will have some starches coverted and the rest mostly destroyed so thats why you can mash or steep. They definitely have had all their enzymes destroyed so they can't be mashed by themselves.
So I spose the question is, how much starch was left in the brown malt I got? The answer is...? I think I might ask the malsters!