You need to reuse to achieve the 50-80 roll number anyway since there are no tanks that will cover a 135 or 120 with just 62mL of developer. Since the first number implies reuse, why not state the higher number for sheets on the same basis?

If you want to be conservative with the one-shot, you can do 230 sheets from 5L in a Jobo 3010 (210mL per 10 sheets).

I'm trying to help you out here in your capacity claims as I think you're being inconsistently/unnecessarily conservative on the 4x5 sheet count.