Linked sheet cell reference incorrectly changes when copied

I use Excel 2003. The workbook consists of 10 worksheets with worksheets 2-10 pulling linked data from the sheet prior to it. This is a fairly large workbook that tracks my companies sales on a daily bases per employee.
Here's the problem I'm having ... when copying a row and inserting it into another spot, the linked sheet cell reference changes but the regular cell reference does not.
Formula: =Y424+Sheetname!Y424 ... once it was copied and inserted, it would change to: =Y525+Sheetname!Y424.
This is a relative cell reference so it should update to the new row number. Some of them do but others do not and it only affects the sheet referenced cell.
Let me try to walk you through what I did ...
All 10 sheets are highlighted (as i need the same change on all) - On sheet1 I highlight the row I want to copy, copy it (ctrl+c or right click copy), then I insert it where I would like (select row, rt click, insert copied cells). Most everything works properly except for a few random cells.
Sheet 1 - 3 will be ok but then sheets 4-10 will have this problem.
This doesn't happen all the time nor is there a pattern.
I've done this a couple of times and each time it's a different cell that will have this problem. It's only affecting the sheet referenced cell and the number of sheets it affects differs too - sometimes sheets 1-5 are ok but 6-10 will have the problem.
I've read in other forums of other ppl having the same problem but there doesn't seem to be a solution other than changing them to absolute references but that defeats the pupose of keeping them relative for updates (additional employees need to be added / moved around)
Any suggestions would be greatly appreciated.
Thank you.