Oh well, If no-one else is going to, I guess I have to set things straight.
Polly, you must - I repeat MUST - only use the very special paper that is sold as RV toilet paper and sold only by RV specialty shops.
If you don't, your long-suffering toilet cassette will develop the most painful case of cassette constipation you have every experienced. The spout will be so blocked with undissolved paper that you will need a jackhammer to clear it. In extreme cases you will have to scrap the whole cassette and buy another.
Can't you see that RV equipment suppliers have only your welfare at heart so have spent squillions developing the special product that is guaranteed to dissolve instantly. Of course it is only natural that this very special stuff is five times the price of normal toilet paper and that is why ALL sensible RVers who understand the mathematics of market forces, research costs and the potential cost of not using it, buy dozens of rolls and stock up at every opportunity.
Don't you believe for an instant the widely held belief among the great unwashed (and unwiped???) mass of ignorant hoi polloi that the only reason smart people buy the special stuff is because they are stupid and gullible and stupid and have too much money. They are just plain jealous and wish they could afford it too.