I would not trust the Jobo flasks for storing chemistry as they are of the soft kind of plastic that is likely to be oxygen-permeable. PETE or glass bottles, either squeezed to get the liquid to the cap or butane displacing the air, should give you better longevity. I plan to store my 1L of developer working solution in the fridge (to reduce oxidation rate).

I believe the Rollei kit is just Fuji chemistry (I read it on APUG, it must be true!). I recently bought the Fuji 5L kit and it says you get 16 rolls per litre of chemistry; people here report that it works well long after that point. You need to increase the development time after every 20% of the capacity of the working volume you're using, and the increases are very small: 3:15, 3:18, 3:23, 3:29, 3:40 (that last one might be wrong). You can find the Fuji instructions scanned and posted in another thread around here somewhere. The times published assume that the exhaustion occurring in one batch is small compared to the total capacity of the chemicals, i.e. that you're using much more chemistry than the "one shot" minimal amount. The Fuji instructions suggest doing 5 batches of 16 films in 5L of chemistry, which means that you want at least 300mL of chemistry per roll otherwise the reduction in activity within one process will mean you want a longer processing time than indicated in the table.

Say for example, you mix up 625mL of chemistry (enough for 10 rolls at the rated capacity) and process two rolls at a time with all of chemistry. Your processing times for the 5 pairs of rolls should (nominally) be 3:15, 3:18, 3:23, 3:29, 3:40. Alternatively, you could do one roll at a time; you would put in about 350mL of chemistry, do the process at the time for that roll-number, then mix the recovered chemistry back with the other 275mL. This is because the chemistry doesn't care whether you're running a 16 roll batch in 5L or a 2 roll batch in 625mL - it's the same amount of chemistry per film.

Or you could replenish; I haven't done it with colour but I believe it works like this:
- make up a batch of chems (working stock), at least 300mL * concurrent rolls (e.g. you want to soup 6 rolls at once, make up 1.8L of chems)
- make up some more chems (replenishment stock)
- run a batch of rolls in the working stock for 3:15 (probably)
- throw out 62.5mL of working stock per roll processed and replace it with the same quantity from the replenishment stock

That 62.5mL is 5000mL/80, i.e. the replenishment rate that will get you the same capacity as reuse. Arguably you could push (reduce the replenishment rate) this further and more safely than you could push non-replenished re-uses.