Peoples opinions differ on the use of R22 dipsticks, some say "always dip before and after flying", others say "dont use dipsticks, they can damage the fuel sender".
A bit like pulling the tail down to check the TR flex coupling, some people do it, but others say 'dont do it - it strains the tail too much' (I think this is what Robinson tell you on the Safety Course)
Personally, I have always trusted the gauges, and have never had a problem after 1,000+ hours in R22s.
I have flown two-tank Schweizer 300 CBIs that have very unreliable gauges, even brand new machines.