Film probably just needs far less washing than fibre based paper. Remember that your sheet film is made of pretty water impermeable polyester, versus the water soaked and contaminated paper base of a fibre based print. That probably makes a huge difference..., as the gelatin layer on the film base is just a tiny layer.
That's very true. I have to check how final wash with only couple of water changes will work with gelatin based roll films. Perhaps they will require a bit more water.