[Solved] Struggle with CMS and reflecting on relationship

Hi any advice on what I can do next?
I seem to be in daily contacts with the new CMS and banging my head against a wall and explaining my situation due to a unreasonable amount of monthly payments being put soon on me. I have had a decent relationship with my daughter and have always paid my maintenance through CSA (£340 PM) When we spend time together there is natural 'expense' as we do things and go places together. I've also been putting away savings for her when a little older. CMS fail to recognise this in any deductions (only over night stays, which we have been working on gently as I have a new girlfriend with a 9 yr old ) and how they have worked out my payments for this year is from income gross earnings from last year which was higher to my actual contracted income due to overtime what was available.
This will not be the case this year and so far I will struggle to make these payments. Not only to support my 'new family commitments' and another child I call my own (which CMS deducted £11 p/w which again doesn't amount to much?!) but to also spend money seeing my daughter and her future savings will be affected. I've had to explain this to my child of 13 yrs old and it's already ruining my relationship as she doesn't want to just be at home and knowing I'm going to be making these sacrifices is upsetting her which is annoying her mother (who has chosen to use CMS), and probably no doubt feeling left out to my step child as it appears.
My ex works full time and has another child by another father which I presume is going through the same situation/agreement as I and her mum looks after my child after school so I can't see there being many outgoings where me and my partner does.
I have submitted an expense form for my contact costs of which amounts to £40 every fortnight to collect and spend a day sometimes a night but it's a working progress slowly disappearing. CMS say this MAY not be deducted (and the only hope I can do to get payments down a bit) and I'm to start my payments in March at £497 pm.
Why can't CMS get this correct now? And or take into what is actually best for the child to see and spend time with her father? I feel I'm caught in the middle to keep the peace and to keep my relationship on one side and to fight the CMS to a more reasonable amount on another..
So by looking on the gingerbread site it seems like the only option I have now is to contest the payments and appeal with the aid of a solicitor at a cost of £150 per hour , go to a mediation and to court for allocated dates for visits (at again my cost), whilst ongoing payments need to be met all at a lower income. And dragging my ex and child through the courts which is only damaging my relationship even further!
Stressed and deflated to this system is an understatement.

Any help or advice would be greatly appreciated.