CSA payments almost halved when exH has not changed jobs - why?

[postmanpatscat]

I asked for a reassessment as it had been three years. No change in number of children, nights etc. CSA have just rung and told me that my payments will go down by around 50% to £54 per week (was £453 per month). Apparently exH would not speak to them or give them any info so they got it from his employer (same one for last 11 years, still doing same job). His payroll dept have confirmed. He works for a huge global company so it's not likely that anyone in payroll has lied on his behalf.

Something is amiss. Why would he hide from CSA and what is he hiding? Who stays in the same job and gets a massive paycut? His base salary 6 years ago was around £80k. He used to get an annual bonus but apparently didn't get one at the end of last year. CSA went through last 52 weeks of data with his payroll dept.

This is the man who appealed when I first claimed as he said his bonus wasn't guaranteed. The appeal was rejected. Why, if he's had a massive paycut (which I doubt) has he not been straight on the phone to the CSA telling them all about it?

[Newtodating]

Is there a chance he's moved in with someone that already has children?that would reduce his payments. Other than that I'm not sure.