Hi, I'm about to finalize my monthly billing report but am left with 1 more challenge...

On my report, column A conatins an order number.
I am am allowed to charge a fee for services provided, but this is 1x fee of (let's say 100 USD) per order. This fee is included on column B.

The problem is that some order numbers are showing up more than once on that report,
and I am currently manually skimming through the report to add the '100' USD fee to each new order.

The file is already sorted by order number, so I am hoping someone knows the code to 'detect' a change in order number, and then for each 1st line of the order number that is detected to change a 100 USD fee.
Any additional lines should be marked with a value of 0 USD.

Thanks