Jeff and Cheryl,
For the jacks, room slide extensions, and (for the Apex) the Smart Beds, the HWH hydraulic system in the small compartment behind the PS front tire is used. Both WRV technicians and HWH technicians stated to me directly that you can use the HWH branded hydraulic fluid in the HWH system, EVEN THOUGH the placard by this system states "Chevron Rykon Premium MV". Either the Chevron fluid or the HWH fluid is preferred over other hydraulic fluids mainly because it is clear and non-staining (if there is a leak on the carpet).
For the Hydromax brake booster, the radiator fan, and the power steering assist, the hydraulic fluid is in a very large cylinder in the PS of the engine compartment. This is a different hydraulic fluid and WRV changed its recommendations for this several times over the years.
See this link for a discussion of these fluids and hydraulic systems (post #14 for my comments):
Hydralic Oil - Pwr Steering/Brakes