Column formula for "greater than" and "less than"...

Column formula for "greater than" and "less than"...

Question: "Is this the correct formula for the example below?" The reason I ask is when I try to place it into the " Add Custom Formula" screen, this error message appears " Specified formula is invalid".  
 
=IF("Total Commission"<=10,"Total Commission", IF("Total Commission">10,"Total Commission"*0.80))
 
             Total Commission       Agent Commission
----------------------------------------------------------------------
 1             $3.00                                  $3.00                      
----------------------------------------------------------------------
  2           $15.00                                $12.00                     
----------------------------------------------------------------------
 
"Agent Commission" Formula Parameters:
 
When the column " Total Commission" is " equal to $10.00 or less", than the column " Agent Commission" equals " 100%" of " Total Commission" ( Shown in Row 1
 
OR
 
When the column " Total Commission" is " greater than $10.00", than the column " Agent Commission" equals " 80%" of " Total Commission" ( Shown in Row 2).
 
I hope I explained that correctly.... as always, I really appreciate any assistance.
 
Thank you.
 
Michael