Hi Laura
The YTD statistics are not date-sensitive. They just keep on accumulating until someone runs Year-end processing. The only way they will agree with the underlying detail is if Year-end processing was run at exactly the right moment - after all of the invoicing was done for the prior year and all of the cash receipts were entered for the prior year.
So if the YTD statistics don't agree with the details in OE or in AR, then it's because the timing of the Year-end processing step was not exact. It's why I don't put a lot of faith in those statistics.
They can be modified. It's a bit of work, but you can create a spreadsheet in Excel with the correct figures and then import them. There are more statistics fields than you may realize, however. I use an Adagio module called Adagio Gridview Read/Write to change the figures for my clients, and it's quite easy, but that is not a module you are likely to own or even know about.
Steve