I understand where you're coming from. Sorry cannot help. We also don't receive FTBs and CCB and we've Bern using up the CCR in the first quarter of the FY but we never ask about the 15% cause we get it at the end of the FY so we consider that as nice savings towards the mortgage.

Maybe ask dept of human services?
You don't have 15% withheld if you are on quarterly payments....