This problem is a limitation of Microsoft Word.  When you insert a column or row in an Excel spreadsheet, Excel automatically updates cell addresses in the affected formulas to preserve the intended cell references.  Word, however, is not a spreadsheet.  It doesn't have the built-in intelligence to adjust formulas for cell reference changes.  However, by using  Formula Builder and the Copy and Paste Table Formula features in the Toolkit, you can quickly and easily update the affected formulas.