I do very much like TCP, much as I liked its predecessor  Accupaint.  However,, the experience of a lifetime of railroad model painting has been with flat finishes (Floquil old, Floquil middle age, Floquil at the end; RPM, Stewart-Lundahl, Model Die Casting, etc.), and where subdued finishes are required, the high gloss RPM finishes -even with subsequent flattening- are a nuisance, decal application ease notwithstanding. 

What we do not have in this hobby (with occasional exceptions) is something in between, paint finishes that are satin, semi gloss, matte (almost, but not flat), finishes that truly reflect more accurate real time appearance.  This is especially true with black, where except in the most egregious locations, the original shiny black paint still should shine through the veils of grime, dirt, stains and oxidation, an overall appearance best represented (before weathering) by a finish not flat, not glossy, but somewhere in between.

i do know about over-coating, i.e. various mixes of Dullcote/Glosscote, and semi-gloss varnish (my old favorite of many years ago).

 

Denny