No, don’t use the total income figure.
You’ll actually have to make a calculation to come up with your figure for responsibility.
According to Change in filing or marital status in the 2021 Oregon Income Tax - Form OR-40 Instructions, [s]ome taxpayers who filed a joint return for 2020 must prorate their kicker based on their share of 2020 federal AGI.
Table 8 seems to indicate that you would need to complete Parts A and B of the Kicker worksheet, since your filing status changed from “Joint” to “Non-joint.” You’ll compute your share of 2020’s federal AGI in Part B.
