A Mod Scaled by Game Speed

I'm working on a mod that would allow for attributes to be affected by game speed. For example, it's known that a particular unit with a Standard Production cost will cost less to produce on Quick or Online game speeds, and would cost more on Epic or Marathon game speeds. But it's unclear to me where that effect of game speed comes into play in the game's various .xml or .sql files, or if I wanted to create similar content, how to code that, for example, to modify how many movements points a unit had as a function of game speed.