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The e-commerce.

Paypal tax calculations wrong?


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I seem to be having issues with paypal tax calculations, I'm pretty sure its not my doing.. and is a paypal 'bug'. I'm posting it here to see if anyone agrees/disagrees. Here is my problem:


I use the paypal IPN module with my oscommerce shop. Lets say for example someone buys 1 item that is $0.45 cents. They are from my state and I need to charge them 8.25% sales tax, ok...

$0.45 x .0825 = .037125, rounded to $0.04 cents tax, for a grand total of $0.49 cents. All is well.


Now we move on to 100 items at $0.45 cents each, for a total of $45.00..

$45 x .0825 = $3.7125, rounded to $3.71 cents, for a grand total of $48.71. All is well there.. BUT paypal doesn't agree. What they seem to be doing is as follows..

(round($0.45 x .0825)) x 100 = grand total $49.00.

They round each and every item and then multiple it by the amount, I end of overcharging the customer 29 cents in tax for the example above.


It took me a while to figure out what was going on.. since oscommerce correctly calculated the tax, but paypal seems to miscalculate the tax.


Am I going crazy, is the paypal way correct? I've tried contacting them.. it took two tries to get them to understand what I was saying, and even then the response was "there is nothing that you or I can do to alter this as it is how the system works." Standard corporate response, GREAT!


I've change the IPN module to transmit a TOTAL amount, instead of listing each individual item, this seems to 'fix' things for now. But I would really like to send each item, as it looks much nicer on checkout.


Anyone else see this problem? Maybe if they get enough emails they will fix it.





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