The 4 hours (equally divided) is closing arguments. There is an indefininte “motions argument” period too.
The House had 7 hours and 23 minutes remaining, of their 24 hour presentation allotment, when they started shortly after 1 pm yesterday.
https://www.congress.gov/bill/116th-congress/senate-resolution/483/text
I figured you’d be here and tuned in today, even if only out of professional interest. It’s good for us non-lawyers to hear from somebody in the business.