Recovering Child Support Over-payment From a Double Dipper

I began receiving Social Security Disability in 2010, and from 2010 through 2016, had a garnishment applied to my monthly payments for my child support by the Department of Child Support Services in California.

Little did I know, my ex began receiving Supplemental Benefits for the children in 2011 based on my claim, payments which were far in excess of the garnishment amount (over 3x the amount I was ordered to pay).

Ultimately, I was able to get a new order in place which reflects the offset, and the garnishment is no longer being applied, the court having recognized that the supplemental benefits satisfy the support order. Ironically, the new support amount is nearly twice the amount previously being garnished (that is how far in excess my ex was over-payed from 2010 to 2016; in fact, she still receives more than the ordered child support amount).

I now want to recover the 5 years of over-payment from my ex (only the amount that I paid directly, not the amount in excess paid by Social Security).

The law in California is very clear regarding recovery of over payment for retroactively modified orders (FC 3653), does this principle apply to my situation?

I have found cases in other States where someone in my exact position was able to recover the over-payment, but not in CA, how much weight would these cases have in a CA case?

I know that there is no question that I am entitled to a credit, but I am seeking recovery.