Have you tried the Activity Report (in Pledge and Recurring Gifts Reports)? That is what we use. The downside to this report is that it does not export into Excel very well; we export it as a PDF. Not ideal but we all know the Report export options leaves a lot to be desired.
Have you gotten your question answered? I'm in the same situation. I don't see a way to get the cash flow report to snapshot at a particular time (last fiscal year). The report always includes payments received beyond the reporting period (current fiscal year).
To my knowledge/memory this has been an issue for some time - not being able to run report for specific date. At my previous org we would run all the reports we thought we would need at end of FY so we would have them when needed. Was easier to make any adjustments and there were a lot less than running them a week or two later.
