Child support arrears & FRO

I have a child support order from 2017 that my ex hasn’t been following. He was hiding what his income was and refusing to provide NOAs. I finally learned what his income is and has been since then and realize he has been significantly underpaying child support. He also hasn’t paid any of the child care fees.

When we went to court he begged me not to register our case through FRO so I didn’t and now I’m obviously regretting it.

My questions:

1. If I register our case with FRO now will they start enforcing support based on the amount stated on the support order where it basically says payor pays amount of X based on 2016 NOA, disclosure for NOA shall happen annually at such date and if any changes are necessary those changes shall take effect on July 1 of each year. Will they use that first amount? Or can I provide their 2024 NOA and have them deduct based on that?

2. can I ask for FRO to collect arrears if I provide their current entire breakdown of what was paid and what is owed?