[Suicide Junkie]

Well, if the 5% figure simply comes from a change in settings.txt, making the max maintenance reduction 15%, then you should be OK.
If the change in in the hardcode, like the part about not going below zero (even with +100% to maintenance reduction), then you're gonna pay 5%.

I doubt that SE4 will choke on your savegame, but you could always just go back to v1.35 if it does.