title: Iterative formula for summing multiple values with multiple conditions
body: <p>I'm trying to write a formula that does the following:</p>
  <ul>
  <li>References a cell to determine which tab/sheet to use</li>
  <li>Matches a column and row for each criteria and returns the value</li>
  <li>Sums the matched values</li>
  </ul>
  <p>The closest I get is an index-match-match formula however there are several limitations including:</p>
  <ul>
  <li>If I add a new Column, then the formula won't pick up on it.</li>
  </ul>
  <p>In the photo below is an example of what I'm after and the formula I'm using for now. The Criteria section A1:K12 is on a separate sheet.</p>
  <p>On my master sheet is the Aircraft section A16:K17 with the columns and rows that form each criteria that I need to sum from the Criteria sheet. Row 1, 2, 3, etc are difference install options.</p>
  <p><a href="https://i.stack.imgur.com/8uPqu.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8uPqu.jpg" alt="enter image description here" /></a></p>