title: sumifs + offset function
body: <p>I´m stuck trying to build this excel function:</p>
  
  <p>I have this matrix <a href="https://i.stack.imgur.com/vyblw.jpg" rel="nofollow noreferrer">(see picture)</a> with quarter year sums and I want it to sum up to the month I indicate in the cell next to "Month", excluding all the quarteryear sums. So far my Formula, as an array: </p>
  
  <pre><code>={SUM(SUMIFS(($Q20:OFFSET($Q20;0;$S$16-1));R19:AG19;AD16:AG16))}
  </code></pre>
  
  <p>Any ideas?</p>
  
  <p>Thanks in advance!</p>