look i no its a bugger gettin xp after lvl 90 but you will find you get more xp from cs runs BUT you can do baal runs much faster and so the xp gain will be greater.
just use x-x-10 anni and ondals and that there is 15% xp gain and so that will save you from 90-99 about 200 baal runs> have fun.
Lvl98-99 alone takes 8k-8.5k solo baal runs, so the 15% exp gain saves around 1.2k runs. But then no sane solo runner will use ondal, the sacrificed survivability and killing speed just don't justify the 5% exp gain. So 10% exp from x-x-10 anni is much more realistic, which saves about 800 runs.