Complex starch is responsible for body. A and B Limit dextrin released during liquefication of amylopectin forms body. Complex starch is heat resistant, it bursts at 169F, dextrinization occurs at 149F. When mash out was performed, due to the high temperature some of the complex starch burst, enzymes were denatured due to high temperature and the starch will end up down stream. Mash out is used in a method in which mash is boiled and where a few different temperature rests are used. Boiling bursts complex starch and during dextrinization A and B Limit dextrin will be released by Beta and Alpha, forming body.
Sweetness develops when Alpha liquefies the reducing end of simple starch, amylose. Sweetness and body are not to be confused. A and B Limit dextrin are tasteless and they are non-fermentable.
Thick mash preserves weaker enzymes, proteinase and beta. Thicker mash allows Beta the time it needs for conversion to take place. The non-reducing chain formed during liquefication of simple starch is glucose. Beta converts native sugar, glucose, released during liqufication of amylose into maltose and maltotriose. It is a molecular thing. Saccharification and conversion are not the same and iodine cannot be used to tell the difference. Starch does not convert to sugar, one type of sugar converts into other types of sugar called di-saccharide and tri-saccharide. Considering enzymatic action, forming a thick mash really isn't a mistake. In my opinion, you did not make a mistake.