While editing a Financial Report, the refresh to the data is automatic when you edit a formula field, and to our knowledge is something you cannot turn off.

As far as the speed concerns for accessing your data, perhaps try doing the same processing with a copy of your Ledger data local, then put the completed specifications back on the network drive. You will find speed is greatly improved. Also, determine if your network connections are 100Mb or 10Mb - the faster the better.

The next release of Adagio Ledger and the Financial Reporter will have speed increases, especially for more complicated reports. There have been a couple of other clients who have experienced similar performance problems as yourself, and and on testing have verified that the new version helps a lot. I can't promise when this version will be released.