Find Phrase In One Column And Apply Formula To Different Columns Same Row?

I am trying to come up with a macro that will find rows that contain the words �as % of Revenue� and then calculate and apply the appropriate formula to the actual and budget columns. I have attached a sample of what the source data look like.

The formula divides the category�s total expense by the revenue in row 4. For a complete macro, I would want to also subtract the budget result from the actual result and put its result in the �better (worse)� column. I need to use this on 12 or so different workbooks which is why I�m wanting a macro.

Here is my attempt to accomplish this task; however, I quickly realized it is woefully inadequate because I neither understand how to apply it to the different columns or how to find the next instance of �as % of revenue�).

VB:
Sub Macro1()
'
' Macro1 Macro
'
Range("B10").Select
Cells.Find(What:="as % of Revenue").Activate
Range("B20").Select
ActiveCell.FormulaR1C1 = "=R[-1]C/R10C"
Range("B21").Select
End Sub