NY state Child Support question?

I have recently put in for a cost of living increase for support; I am the custodial parent of our two children. Here is the question:

X husband pays the standard 25% for the children. He has two other children by his second [now also x] wife. IF he is paying support for all four children, does he pay the 25% to each custodial parent, or is it the standard 31% then split between the custodial parents? I have the Child Support Standards chart, but this particular scenario is not addressed and I am having difficulty finding the answer. Is there anyone in a similar situation [even if in a different state] who can shed some light? Looking for emphatic answers as apposed to an educated guess. It is unclear as to weather or not he is paying support to his other children at this time. Thanks for taking the time!