electrician question: voltage drop at outlet to TT

I never plug my RV directly into any outlet at a campground; I use a Progressive Industries box that monitors amps, voltage. So I am monitoring voltage at the source NOT in or at the RV.

Based on what jodeb720 and azrving posted, my voltage drop is excessive. So that is now the question: Do I need to hire an electrician to run a dedicated line out to where the RV plugs in?

Also FYI, the AC has a slow start device so it doesn't kick in immediately and overload the generator when using that.