I have been using the Kodak Flexicolor chemistry with a Jobo CPA-2 exclusively for close to 2 years now and alway got good results by following Kodak's instructions. If I want to process 2 rolls of C-41, then I'll mix enough developer (660mL) to develope those two rolls and toss. I'll mix enough bleach and fix for 1 roll (330mL - Kodal says you can process twice the number of rolls as with the developer without replenishment) and toss. If Kodak says to put starter in, I put starter in. If you use Kodak chemistry, you won't go wrong now or down the road by following their instructions. After all, they developed the process.
Developer is cheap - like $2.00 per Liter. If you mixed 1 Liter to process 3 rolls, your per roll cost for the developer is about 70 cents. Fixer cost is very little. The expensive part is the bleach and that's why you reuse it once.
Thomas