[2008] ReportViewer page count

Hello,
I'm new to the ReportViewer and .rdlc files, and I'm wondering if there are any reasons why the ReportViewer page count might be different to the actual page count when the report is physically printed?
For example, when I view the report on screen in the ReportViewer, its showing 3 pages, but when the report is exported to PDF, or printed, there are 5 pages.
I've sized the paper layout in the .rdlc file to A4 landscape, and it prints on A4 landscape, but I'm getting more rows of data on screen than on the actual printed report.
Anybody got any thoughts?