I created a custom function (See below)
Which takes validated input from 7 other cells parses using MID and
concantenates and returns the result into an 8th cell. WHen I change the
contents of any of the cells the value is not updated in the 8th cell...Even
if I press F9 it wont update it. I have to place the cursor in the 8th cell
and press enter once to get the updated value.

Is there a way to correct this behavior? In my options I have auto
calculate turned on.