Floquil has always been flat lacquer based paint, not enamel. It consists of the actual color pigment and the liquid it is dissolved in. It does not have a "binder", the product that gives paint body, and provides the gloss. That's why modelers have liked the paint, it goes on relatively thin and does not cover details, and dries relatively fast due to a lack of binder. They offered their clear "Glaze" that could be added to paint if a binder was wanted.
Having said the above, please note this is the way Floquil paint used to be. They've been tinkering with their formulas in the past while, and I assume things have changed. So older paint may be flat, but newer stuff may not be. I haven't bought much in the past while because I have a fair stash, and not many dealers carrry it in these parts.
Also the older paint would go on really flat when using an airbrush, but with somewhat of a sheen when applying with a brush. I assume that was because there was much more paint applied with a brush.