I am learning several rather confusing facts this year about coleus cultivars.
1. My "Solar Eclipse" had more intense color when I first rescued it from the full sun storefront sales rack...
2. I managed to sunburn my Sun Coleus "Pineapple" by attempting actual full sun treatment in a well watered 3 gallon pot.
3.All of the cultivars (Solar, Sun, Exhibition Giant, Wizard, Oakleaf and Rainbow) are responding well to very bright indirect sun (as in just outside the reach of the direct sunbeams on my southwest facing porch) and are keeping the kaleidescope colours coming on this month.

I don't think your Coleus could be getting too much sun inside. If they are not making flowers at this time of year, they are deprived of light. I never mist my Coleus plants that come inside for the winter.

I have found that if I water certain colei?(coleuses?) while the sun is shining on them, they will fade dramatically to soft shades of pale yellow, pink and green. They looks like new varieties that go well with other pastels. So at this point, there are a few plants I do it intentionally to.

Springcherry