Maintenance payments from Ex on benefits.

carlos1973

I've just discovered my ex is getting an additional payment from DWP that she had not told me about previously.  She gets Universal Credit & PIP and has always insisted that the PIP bears no relevance to the amount she has to pay me.  I have now found out that she also gets around £400 a month extra as she gets LCWRA.
For the first 3 years that we were apart she paid £30.30 a month and last year she begrudgingly increased this to £35 a month.  The 2 children do not have overnight stays with her due to safeguarding concerns.
On the CMS calculator if I put the total monthly income she gets as if it was was a salary then her monthly contribution increase from £30.30 a month to £125 a month.  This is a sizeable difference and would definitely ease the struggles I have raising our 2 children.
I feel It's reasonable to ask her to increase her contribution to say £50 or 70 a month as she makes no other contribution to them.  If I go to the CMS would they increase her payments due to the additional £400 a month?
Any comments or advice welcome.

On a separate topic why does the CMS not increase contributions with annual rises in Universal credit, COL payments etc?