You can NOT change the number of decimal places that will show in reports for exchange rates - it seems to have been hard coded for 2 decimal places for some bizarre reason.
The specific report I am trying to run and export is:Reports => Investing => Investment TransactionsWhere my investments are held in USD and I need an ACCURATE export of the associated exchange rates.
Printing out the exchange rates from currency list is useless as the rate can be overridden in a transaction (and in my case often is)
All I want to do it to check the exchange rates in my investment transactions by exporting them out somehow - but 2 decimal places is useless in forex.