Typically the suggestion is to have not less than 125 ml of fresh stock pre 80 square inches of film (1 - 35mm x 36 or 1 - 120 or 4 - 4x5 or 1 - 8x10). I know this contradicts what the Xtol data sheet says, but the data sheet is also assuming that you using the entire 1 liter, or you are putting the used developer back into the container of fresh. AND typically capacities are understated to ensure that the developer works properly. If you have older developer, not stored well, the capacities stated are probably still OK, if fresh (just mixed) you have more capacity. Thus the difference in recommeded minimum amounts of stock.(posted 8681 days ago)I just checked the data sheet, and above the table of capacities (rolls per liter) the section on diluted developer does state minimum 100 ml per 80 square inches. The table IS for undiluted developer.
I have however, always maintained, that with extended development time you could go as low as about 70 ml per roll, which is what you figured out from the table. The only thing is what the time should be based on, Kodaks table of 200 ml per roll, their statement of 100 ml per roll, or the standard suggestion from users of 125 ml per roll.
Thanks for the work.