ok suggest exploring what else happened to this security since acquisition... did you only have ~51 shares in those statements and the ~21 were awarded later? - I was just looking again at all these pairs by acquisition date, they have the same ratio of ~2.4 to one. Feels like it was a stock split or spinoff of some sort, so you need to understand what happened to get the right tax treatment and cost basis, I would look thru the later statements to see what happened and when the share count increased and why. If it was a corporate action there is usually some sort of term sheet which explains the tax consequences and may make sense of how this is being reported (it's possible the basis has been adjusted for some reason and reported correctly, and maybe 0 is the correct basis on the smaller lots if they were awarded as part of a corporate action but you didn't acquire them for cash).
