They're wrong. The new rent control law (effective Jan 1, 2020) specifically excludes temporary discounts from the base rate calculation. See section 1947.12:
https://leginfo.legislature.ca.gov/faces/billTextClient.xhtm...
https://leginfo.legislature.ca.gov/faces/billTextClient.xhtm...
Note that SF-style rent control was outlawed statewide in 1995 by Costa-Hawkins. Only cities with existing program at that time can continue them.
> specifically excludes temporary discounts from the base rate calculation
I think you two (three, including "this commenter") are in agreement…
The second commenter (me) is saying that those discounts don't count towards the base rate.
SF does not include temporary discounts in their base rate calculation: https://sfrb.org/section-372-definitions