What would happen to my redundancy package during CSA payments?

I am under the new child maintenance options, needless to say i have got ongoing complaints re wrong information given to me by csa before.

Can anyone tell me if i accept a package to leave my job< £30k is tax free and £10k is not, per guidance it states they look at your gross taxable income (surely this would mean the £30k tax free payment would be exempt). Has anyone come across this or been in similar situation? Any help would be greatly appreciated.