I’m having this issue too. I ran out of water once during a brew cycle, and I suspect there’s an air bubble trapped somewhere in the system, causing it to use more water than it should. I’m not sure how to get that out though. I tried brewing a full carafe and it was on the nose correct. 1 regular cup of classic still yields anywhere from 9 7/8 oz to 11oz (using a kitchen scale to measure).