Always use light coats with any kind of laquer coat--if not, you'll wind up running the risk of "crazing" or "fogging" the paint---bleaching the pigments out of it. It looks like a white or fogy sheen over the model. Gloss needs a few coats to fill in microscopic surface irregularities (which fracture light waves into "dullness") and properly reflect light, ie, to "shine".
You may be thinning it too much?...try a slightly thicker ratio.