You think you've worked on it far more than you have. “I'll work on it this weekend” isn't a commitment: it's an intention, and the first thing that comes up pushes it aside. On Tuesday at 9:15 p.m., though, there's a slot already booked, with another person on the call.
People who run a project in the evenings often get two things wrong: they overestimate the hours they've put in and underestimate how much is left. There's only one way to correct it: look at the log instead of your memory.
Here, at the end of a session you can rate how it went from 0 to 10, if you want: when you do, the hour counts as minutes times the rating divided by ten. The rating stays next to the session in the log, and the number you read isn't the one you remember: it's what happened.
No. Each of you works on your own thing, in silence: at the start you say in one sentence what you'll do, nothing more.
You do, at the end of the session, and only if you feel like it: it's optional, and it's the one thing the app doesn't decide for you. Weighted hours only come from timed minutes, and those can't be typed in by hand.
Yes, there's a slot every quarter hour, every day: you can come back to the same appointment as often as you like.