1L of E6 chemistry will develop about 10 rolls (40 sheets) of film without its rate dropping off significantly (Fuji instructions say to extend FD by 30s (8%!) for the second half of the rated capacity to maintain appropriate contrast), whereas you can fit maybe 6 rolls (3 spirals in Multitank 5) or 10 sheets (3010) in at once. There's no way you're going to run out of developer activity with a push and a full litre of developer.
Also, most of us set the Jobo bath to 38.0C. That puts the tank contents at about 37.8C in a 24C room, according to Jobo. And E6 is happy with being a degree or two out (must be between 36 and 40 IIRC) as long as you're consistent and adjust your FD time accordingly.
PS the bleach & fix have more capacity than the devs and since they're to completion, I just run them a couple minutes longer to be sure. Also the reversal bath and pre-bleach, so you can be more-sparing with replenishing/replacing those, though they're pretty cheap compared to bleach. One of my local labs (the struggling one) was saying that they were having issues with pre-bleach going off; the effect isn't visible in the slides immediately after processing but the slides degrade rapidly thereafter apparently, so keep your pre-bleach fresh. And do not rinse between pre-bleach and bleach, there is an expected/desired chemical reaction between those two baths occurring in the film.