I don’t think the numbers in the “prior year” column get sent to CRA - it’s just for your info. Not 100% sure on this, but I have accidentally filed T2 returns with incorrect numbers in the “prior year” column, and nothing changed at CRA. When I review that prior year’s info on RAC, it remains the same as when it was originally filed.
In any case, I would enter the “prior year” column as it was actually filed - so you have it as reference.
P.S. This relates to my request that Tax Cycle implement importing the prior year info from .COR files downloaded from CRA via AFR: