CSA change in circumstances

TinyChoo

Hello,
Pls could I get some advice?
I recently moved in with my partner. I have a child with my x and so does he.
I receive money from my x for my son (d debit, settled between us, on good terms). However, my new partner pays through the CSA and communicating with his x is not an option at the min.
Because my boyf lives with me and my son and I work is he liable to pay more or less through the CSA?
I've read differing opinions-some stating he will pay more because I work and some saying he will pay less because he has a child living with him (despite not being his biologically).
His x has started working, has a child from a rship prior to my boyf, lives with her parents and has a new bf though don't know if they're planning on cohabiting.
I am very confused and can't get a definitive answer anywhere.
Worried as I heard she could take MY sons CTC and my wages??!!!!
Please advise x

Caz3121

his ex-s income and who she lives with is irrelevant
Assuming on CSA2
He would receive a discount based on the fact that he has another child in his household. They will include WTC in the assessment if he is the higher earner only. Child tax credits will be included (this may offset the discount)
eg before living with you (assume income £1800 and £200 per month CTC)
CSA @ 15% = £270 per month
now income £1800+£200 = £2000, less 15% for the child living in his household = £1700 used for CSA = £255 per month

obviously the formulas will differ depending on income and tax credits but in many cases use of tax credits and the discount will cancel each other out

TinyChoo

Thank you.
We're only going to get around £20 WTC as a couple. Know he has to inform of change of address....is it worth/necessary that he mentions me and my child? Says he doesn't want to rock the boat and continue with same payments.

TinyChoo

CSA claim was end of 2013 if that's relevant?