It should be pointed out that because average daily currency rates are used, the accuracy of these fiat conversions depends on the degree of market volatility. Also, when rates vary significantly between exchanges, such as recently with respect to SBD, I'm not sure how the historic prices from cryptocompare.com are determined. I think they prefer the Bittrex to Poloniex prices though, and the internal market seemed to follow that pattern too.
The utility of these reports will be limited if you do much intra-day trading since it is possible that each transaction (even in the internal market) is a 'taxable event' as far as tax authorities go.
I am not aware of a source of historic currency data at greater than daily average resolution. If you are aware of such as source, I'd be pleased to hear from you in case it's possible to build this into future reports.
It would be nice if the tax situation wasn't so confusing, and good luck! ;)
