you shouldn't need to determine proper cost basis. There should have been a supplement schedule with the info need to compute gain/loss on disposal
it might be labeled as 2023 sales worksheet
here are the typical columns on such a worksheet
1. units sold obviously it should be 300
2. sales date
3. sales proceeds - enter from 1099-B
4. average purchase price/ initial tax basis amount - should be a number
5. cumulative adjustments to sale that should only be the profit/loss and distributions attributible to the shares sold
6. average cost basis which should be column 4 less 5
7. gain subject to recapture as ordinary income. this is the only nuber that gets entered in the k-1 ales section as sales price and then as ordinary gain. flows to 4797 line 10. this could be zero or not present. the amount adds to your tax basis for purposes of schedule D/Form 8949, do not use what broker reports as tax basis
8. percent long term
there may be other columns
you can do a rough check of how accurate in total your profit and loss allocations are for each lot by taking
column 5 and subtracting the distributions received on the 300 share lot. the remainder would be the total of profit or loss for that lot
another way would to be to use schedule L
for capital contribution use the purchase price of the 500 share lot
subtract the distributions for the 500 share lot
subtract ending capital account - (this is the tax basis remaining of the 500 share lot)
the result you get should be close to the profit/loss allocated to the 500 share lot
the results under either method may not agree with your calculations.
2 k-1's are only necessary if there are business lossses showing on line 1,2 or 3.
losses on these lines attributable to the 500 share lot are not deductible due to the tax laws for PTP
while for the 300 share lot they would be because of complete disposition. if they're profits segregation on two k-1s isn't necessary because all the income is taxable.
