Looking at it from a ratio standpoint, for every dollar that Sere's acquaintance brings home, the ex is getting three. Ergo, she is 'making' three times as much as he is, to cover herself and one of the children. Doing the same thing with the other man, (I'm assuming a similar proportion of garnishment) and again, she's 'making' three times as much as he is to cover herself, and the other child. Assuming that she divides the funds evenly between herself and each man's child, Child A is getting 1.5 times as much as what Daddy A brings home, Child B is getting 1.5 times as much as what Daddy B brings home, and she's getting 1.5(Daddy A) + 1.5(Daddy B).
Compared to the men, even with children, she's probably doing OK.