ah, i think i just found the missing part of the problem.
i have been using your mod together with Vill's Recipe Randomizer and that seems to have caused a good part of the compiling time increase as well.
i have just tested using only 248k mod or krastorio2 with either one or both of the randomizers and while there does seem to be a slightly higher loading time than expected when using both randomizers, Vills recipe randomizer is just particularly bad with the 248k mod.
seems like your mod is innocent! sorry for the inconvenience!
i'm gonna post this on Vills mod page instead.