Kodak's replenishment recommendations are for when you're using XTOL full strength, i.e. 250ml per roll. You can continue to do that up to 15 times per liter by increasing time, replenishing, etc. This does not really work out to 67ml per roll--it's still 250ml a shot, which you are reusing. This isn't a very good idea either, by the way, as the poster above notes.(posted 8817 days ago)Kodak's 100ml recommendation is for when you're diluting XTOL. In ohter words, if you want a 1:3 dilution, you should add 300ml of water to your 100ml of XTOL and develop in a two-reel tank. If you use less, you run the risk of incomplete development, lack of contrast, etc.
In fact, some people, notably The Film Developing Cookbook, say that 250ml should be your minimum per roll no matter what the dillution, just to be on the safe side. They make the point that of all the places you might skimp, why would it be on developer for your irreplaceable negatives?