Multiplication formula in Excel did not transfer to the iPad Numbers app

I just downloaded the NUMBERS app to my iPad (running iOS 7). I then imported an EXCEL file that I needed for a meeting. It seemed to import well. However, I soon realized that basic =SUM formulas were still intact, but a simple multiplication formula (just multiplying 2 cells, i.e., =MMULT(C38,E38)) which was very necessary to the spreadsheet was not imported. Only the final number in the original document appeared. While I was able to add a multiplication formula manually to that cell, it became a nightmare because I realized that every cell which had had a multiplication formula no longer had one. So, does NUMBERS not import multiplication formulas? Is there a way of saving the EXCEL file so that it will? Is there a way of configuring NUMBERS so that it will transfer them? If not -- and the spreadsheets I need always have simple multiplication formulas -- does anyone know if Apple gives refunds?