New houshold, yes. New family, yes. You don’t get to pick which kids you favor or not. You’ve formed a new unit. That doesn’t mean the bio parent is out of the loop. The deadbeat bio parent (and there are many stories on CC) is still evaluated for a share. (With few exceptions.)
This isn’t a tick list- Bio A $$, Bio B $$, Step A $$, Step B $$. You fill out the dang CSS Profile wth the details and it’s calculated by the college.
Rather than talk about a woman with a wealthier new spouse and deadbeat ex, think of the woman now not working, with the high income new husband. Should she be considered same as an unemployed single parent?