Hospitalization/ICU/Vent utilization question

This is a great tool!! Kudos!!
This more like a question not an issue.
I was looking for the build_admissions_df sub function and have a question.
So, it looks like, e.g. hospitalization number, was based on "disposition".
And the "disposition" was calculated from "i_hospitalized_v + r_hospitalized_v" in parameter.py.
May I know why the number of hospitalization = (i*hosp_rate*market_share) + (r*hosp_rate*market_share)?
Finally, thanks for hard works and efforts on this great tool!
Thanks!!