yes income that adds to basis/cost would include the following (2021) k-1 lines in part III. 1 thru 3, 4c, 5, 6a, 7,8,9a,9b, 10 and 11
less lines 12, 13, 15 and 18. these lines vary from year to year because the IRS revises the form
you can take the ending capital amount from 2020 and then from section L in 2021 add the current year's net income and other increases or subtract if other (decreases). in theory that should leave withdrawals and distributions equal to the final check you got and your ending capital will be zero. if withdrawals and distributions amount are more than the final check then it's likely you got other payouts during the year. The other payouts, if any, would also reduce your basis/cost
put another way your basis should equal the final distribution amount because you start with what you put in add the net income each year (or subtract the net loss) and subtract all distributions other than the final one.
