My 1099 from Fidelity broke down capital gains by long and short term, but didn't sum the costs or proceeds (giving only the combined proceeds). I went to the website to see if they had a better report there. Good news; they did. Bad news; it didn't agree with the paper 1099. I called customer service. They had a third value, and advised me to speak to my investment manager.
He took a few days, but assured me the paper 1099 was correct and was the information reported to the IRS. Should I be comfortable with this?
Interestingly, the online short term proceeds and the online long term proceeds summed to the paper proceeds; so I used them with the paper gains to determine the costs; even though the online gains were different. I hope that makes sense.