I have been trying unsuccessfuly to write a formula to handle the following
We charge a fee (based on a formula)depending on a number of occurences that occur on different days.  If the occurence takes place on the same date no fee is charged.

The first occurence is always free
occurence 2 to 5 is charged at $75
6 to 10 is charged at $150
11 or more is charged at $175
however if the occurence occurs on the same date there is no fee and that occurence is not counted when applying the  formula below

I created the following formula:
if {Command.TYPENO} = 1 then 0.00 else
if {Command.TYPENO} in [2, 3, 4, 5] then 75.00 else
if {Command.TYPENO} in [6, 7, 8, 9, 10] then 150.00 else
if {Command.TYPENO} > 10 then 175.00
else

0.00

The problem I have is changing the fee for the situation where an occurence is on the same date and therefore that case is treated as it never occurred and does not impact in the calculation to determine the fee.

For ex: 
Case 1  3/3/10   $0
case 2  3/4/10   $75
case 3 3/12/10  $75
case 4 3/30/10  $75
case 5 5/14/10 $75
case 6 5/22/10 $150
case 7 6/2/10 $150
case 8 6/11/10 $150
case 9 6/11/10 $0  (Same date so it is zero)
caae 10 7/13/10 $150   (this case now becomes case 9 as far as determining the fee)
case 11 7/21/10 $150   ---Note this is not $175 because case 9 was tossed so this case is really only case 10

Can anyone provide guidance???