If you have a rear kitchen and a mid-trailer bathroom, or vice versa, you probably have two tanks, BUT, you should have 2 grey water dump valves. Could be they just used the dispaly that shows 4 tanks.
Mine has 2 grey tanks that were never mentioned during our PDI, but then the knowledgeable “tech” said our slide was hydraulic when in fact it is rack & pinyon.
__________________
Lee & Kathy, and our alarm clock Jake!
2017 Starcraft Autumn Ridge 266RKS 50 amp.
2017 Toyota Tundra Crewmax 4x4, 10-1-2021