How to handle the change of use of property, and the "plus one" rule

[timc]

I had moved out of one home (House A) in 2020, and into another (House B). I rented out House A.  In 2022, I sold the House A.

For my principal residence designation, I'd like to do the following:

2019 - House A

2020 - House A and B (the plus one rule)

2021 - House B

2022 - House B

I need to report the sale of House A in 2022.  The "Number of tax years ending after acquisition date" would be 3 (2020 - 2022). 

But I can't seem to get UFile to properly assign the "plus one rule".  If I Designate 2020 as the principal residence, UFile will give me one extra year in T2091 (a total of 2 principal residence years), meaning I'd get a capital gain of 1/3 of the total capital gain.  But if I don't designate 2020 as the principal residence (ie. I leave that section blank), the line 20 of T2091 (Line 4 plus 1) is set to 0, and I'm on the hook for the entire capital gain.

Could someone help me understand how to set this?

[timc]

To be clear, I want to designate just one year as principal residence.  But UFile can't do that - it only gives me 0 years, or 2 years.