we are in MA...if BM files, what are her chances at an increase?

fiance's income has gone up about $20K since CS was last set. he now also has an apartment and utilities that he is responsible for (he lived at home before, so he had no expenses other than a car payment and the family health insurance). BM still lives with her parents, has zero living expense, zero bills in her name. she still chooses to work only 16 hours per week despite SD being 14. she flunked out of school so she can no longer say she's working PT because she's going to school.

i know our state is one of the worst, but is there any hope?