Newbie question

Until about 6 months ago. I bought and sold on exchanges like coinbase and kucoin.
Recently I have been using Dex like Spookyswap.

Now transactions on exchanges are timestamped and dollar value is recorded.
But looking at the blockchain scan like FTMscan, the info about the transaction are timestamped but I noticed that the dollar value of FTM is not at the time of the transaction. But the latest market price.

If the value keeps on changing, how does Cointracker handles this?
Or are there additional manual steps that I have to do for these transactions?

Thanks