Thanks @nexchap. An interesting and related aside, Tax Support Package, at least for DBA and DBC, do not actually interpret "unified" as average cost, rather they track a basis for each lot and sell each lot proportionally when a stake is disposed.
Example:
Lot A: 75 units purchased for 2205, price per unit is 29.40
Lot B: 75 units purchased for 1875, price per unit is 25.00
Lot C: 62 units purchased for 1575, price per unit is 25.40
Average price per unit is 26.67
Now 35 units are sold. Total share is 75+75+62 = 212 units. 35/212 = 16.51% disposition.
13 units from Lot A are sold (75*.1651 = 12.38 -> 13), basis is 29.40*13=382
12 units from Lot B are sold (75*.1651 = 12.38 -> 12), basis is 25.00*12=300
10 units from Lot C are sold (62*.1651 = 10.32 -> 10), basis is 25.40*10=254
Total "purchase price" for the 35 units sold is 382+300+254=936 not 35*26.67=933 as would be expected using average cost.
This information is available only online from Tax Support Package under the "Sales Schedule Breakout".
This leads me to believe the wash only affects the cost basis of a specific lot, but yes, I will call Tax Support Package this coming week.
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A somewhat related question: I am given a percent long for each sale, though lots sold tracked by the broker and partnership differ, so the situation may arise where the 1099-B list a short transaction and reported to the IRS, but a percent of the sale is actually long (and vice versa). How does one handle this? My initial guess is to adjust the basis for whatever is reported on the 1099-B for this sale to make the gain is 0 and then create new Type C and Type F entries on the 8949 splitting whatever is reported on the sales schedule with the K-1 to match the short/long ratio.
