title: Sum Column based on date in header
body: <p>I need assistance with a formula to sum data in columns based on a date. My data is below.  I am trying to write a formula or VBA to sum the data for all hours charged by Acme employees after 5/22/15.  I've tried SUMIF and SUMIFS formulas but somewhere I'm missing an important element.</p>
  
  <pre><code>NAME        CO  5/15  5/22 5/29 6/5
  Marco Polo  Acme    8   5   8   5
  Ms. Piggy   Acme    6   6   8   6
  Kermit Frog Mejot   8   8   6   8
  John Doe    Mejot   4   8   10  10
  </code></pre>