I have felt children of divorce get short-changed in the f/a process. Yes, there are 4 people producing income, but there are 2 households being supported.
I'm pretty sure that is taken into account. They don't just add up 4 incomes and give the same EFC.
4 people producing an income of $150k does not net the same EFC as when 2 married parents are producing the same. There is some amount (maybe $25k) that is assumed to be kind of basic household costs.
I think each household is calculated and then the EFCs are totaled. So, if one household only earns $50k, that EFC may only be $5k. And if the other household earns $100k, that EFC may be $20k. So that produces a "family contribution" of $30k...and the fact that there are two households was included.