title: getCalculatedValue reports different response to exported spreadsheet
body: <p>I am working with a fairly large, complex spreadsheet (there are 6 sheets, each with 200-400 rows) and am having trouble getting the correct values out of some cells.</p>
  
  <p>My workflow is roughly:</p>
  
  <ol>
  <li>User data is inputted on front-end</li>
  <li>Data is validated and then placed into certain cells on the spreadsheet</li>
  <li>Calculations in other cells reference the user-input cells</li>
  <li>I use <code>getCalculatedValue</code> on particular cells to retrieve the necessary values</li>
  <li>For debug purposes I then save out the modified spreadsheet so that I can easily see that the data has been inputted and generated correctly.</li>
  </ol>
  
  <p>PHPExcel has been working great, but I have ran into an issue where the <code>getCalculatedValue</code> method (step 4) is returning an incorrect value, but when I inspect the spreadsheet that has been saved out (step 5) the values are correct.</p>
  
  <p>The calculations consist of general mathematical equations, IF conditions, some date manipulation and multiple VLOOKUPs.</p>
  
  <p>I am currently picking my way through the calculations in order to trace the issue, but was wondering if there may be a simpler solution to this that I am not aware of. Perhaps some setting that affects the outcome of various different calculations? This may even be a subtle change in calculations that is subsequently snow-balling into a bigger change further down the line.</p>
  
  <p>Thanks in advance.</p>