Make sure you're using the Copy Table Formula feature to copy the formula, and the Paste Table Formula feature to paste it instead of the regular copy and paste functions provided in the core Word product.  When you use Paste Table Formula it does not pull the copied formula from the clipboard.  Instead, the Paste Table Formula feature accesses the formula from a special location in your computer's memory placed there when you use Copy Table Formula .  Placing the contents of a copied formula on the clipboard would not allow Paste Table Formula to analyze and modify cell addresses in the formula as the needed to preserve relative cell references.