Export to Excel from Crystal-wrong numbers shown in Excel

We are running Crystal Reports V 11.0.0.1282.

A report was written a while ago and it contains a cross tab within a sub report.

When we run the report in Crystal the account balances are correct.

We then export the report to the "Microsoft Excel 97-2000 (XLS)" Application.

The cross tab balances shown in Excel are different to the ones shown in the Crystal representation of the report.

This is also an INTERMITTANT issue. Sometimes it does this some times the Excel numbers are correct.

Has this been identified as a bug in this version of Crystal?

Thanks

Malcolm