Both ends of that range can happen. Timing depends on interviewer availability, office scheduling, recruiting volume, and whether the firm is trying to meet another offer deadline.

Do not assume a long gap means bad news or a short gap means you are a preferred candidate. Scheduling logistics create a lot of noise.

Prepare for final round before you receive the R1 result. If you pass and the next round is only a few days away, you want to be refining rather than rebuilding your preparation.

Mine was 4 days at one firm and almost 3 weeks at another.

Definitely prep final-round fit stories before you know the R1 result.