I am sure you will get used to the positive to positive thought in a while. I do negative to negative on direct duplicating film and it was making my head spin for awhile until it clicked for me that I can't think in terms of increasing anything, I can only think in terms of reducing things. The direct dupe film will process out completely black unless I inhibit it by either using shorter development or more dilute development or by exposing it to light. Once I started thinking of using light to inhibit something rather than to build something it all made better sense to me.