CMS Calculation - Children living in the same house as XH

[CuppaTeaAndAJammieDodger]

I am close to getting the CMS involved as my XH has been very sporadic with maintenance payments for almost a year now.

The thing is when I try to work out how much he would pay using the CMS calculator it asks about other children in the house (his). There are 2 other children living there at the moment, but they are his niece and nephew (along with their mother, who is XH's SIL - they will probably be there for a few months longer) and he has no responsibility towards them financially or otherwise.

So my question is, do these 2 children count in the calculation?

My ex husband got a 20% discount for two children living in his house (partners children) and their father paid maintenances

No, they should only count if he is in a relationship with their mother.

Thankyou MrsBertBibby - that's what I thought, but the info online is so ambiguous.