Yes, the color count in my pics always seems to go to the skies...sometimes I set a goal to myself, like "32 colors max", but then eventually cross this limit, and after that happens then I basically stop caring about the colors and add more and more. And most of the extra colors go for anti-aliasing, which however, as you said, barely makes any difference to the smoothness of the image. :)

I checked the optimization image you made, and see what you mean...and I know that with careful planning this pic could probably be made with 16 colors, and in fact that thought was haunting me all the time while I was drawing this, anti-aliasing those speed beams, with the 64 colors milestone coming closer and closer lol.

So yeah, I'll try to get better in color control in my future pieces.  :)

you need to tone down the way you're handling colors in those larger pieces. not because you're not free to use as many as you can, but rather because you're not really making your image more smooth nor detailed at all. you can achieve a much better contrast by being more careful with your palette and get a far more crisp result if you actually pay attention to the overall contrast of your color choices.

i made a rather blunt optimization of your image(and went from 62 to 19 colors in total) that aplies to mostly everything you've uploaded so far. there's plenty guides on the forums about understanding color optimization and development that you can read to get a more indepth info of what i'm talking to you.