Help with calculating P/L

My P&L calculations are off slightly. I've isolated the problem down to a difference in how I and Oanda are calculating PIP values.

After closing a position (where the base currency is the same as the account currency) is the value per PIP calcualted using the entry price, exit price or some number in between? It seems to be the latter but I can't pin-point exactly how this number is derived.


If entry is 1.43166 @ 3,000 units and exit is 1.43270...
I use the entry price:
.0001 * 3,000 / 1.43166 = 0.209547
Or exit:
.0001 * 3,000 / 1.43270 = 0.209395
But:
Oadna is using 0.209385 (or a price of 1.43277)

Can anyone shed some light on this for me?

Thanks!

have you checked the Full Transaction history spreadsheet from Oanda web (linked from the platform's Account menu) for the numbers they used?

It looks like the problem I was running into has to do with the spread fluctuating. I didn't realize that it will change as often as it does and was assuming a .9 spread in my calculations.