Previously, when I examined rquotad, I did not work as I expected. I will try to verify again.
I gave up on NFS quotas - it was a while ago, but I seem to remember that it sort of just about worked with an EXT4 server file system, but was a pig with an XFS server. My instinct is that it shouldn't have mattered what the server file system type was, but quotas are inevitably implemented differently and it just didn't work very well. It wasn't mission critical, so didn't pursue it.
P.