Personally, I'd do a maintenance myself. Oil and filter changes are easy. Lots of tutorials here. Messick's site used to have a fairly good tutorial on a lot of the B series machines.
Messick's Farm Equipment Service
For the HST, use Kubota Super UDT and Kubota parts for the filters. Done deal.
The bolt head for the transmission strainer (on my B7800) is a 26 mm size. Had I known this before hand, I could have zipped right on through the maintenance exercise. I had to stop and go find a socket that size.
Your labor is free.....Just sayin'.
Thanks for the heads up and the link, some great tutorials/pics on that site!