PayPal IPN Currency/Amount Mismatch: converted_amount

I've looked through dozens of threads regarding similar issues, but no one else seems to be experiencing the exact same issue. And none of the solutions worked.

Our site is dropping orders for Canadian customers only. The PayPal payment goes through fine, but the IPN seems to get stuck on:

Sep 22 2009 13:09 -- IPN WARNING :: Currency/Amount Mismatch. Details:
PayPal email address = [email protected]
| mc_currency = USD
| submitted_currency = USD
| order_currency = USD
| mc_gross = 64.25
| converted_amount = 65.21
| order_amount = 65.21

No matter the order total, the "converted_amount" is always $0.96 off.

We only have USD currency setup.

There is taxes applied for Canadian customers, however this still happens when there is no tax applied.

Edit:

I had upgraded to the latest version: Zen Cart 1.3.8a with the same result.

It should also be noted that this problem only recently started to happen. The hosting server is under our complete administrative control, and there have been no modifications that should have affected this.

Sounds like you have some sort of surcharge addon module installed?
What are all the Order Total modules in Admin->Modules->Order Total?
What are the currencies and exchange rates in Admin->Localization->Currencies ?

DrByte:

Sounds like you have some sort of surcharge addon module installed?
What are all the Order Total modules in Admin->Modules->Order Total?
What are the currencies and exchange rates in Admin->Localization->Currencies ?
Discount Coupon ot_coupon
Shipping ot_shipping
Sub-Total ot_subtotal
Tax ot_tax
Total ot_total

For currencies, just the one: US Dollar (default) USD 1.00000000

We have found that it has something to do with the taxes which are only applied to Canadians. This happens with the orders that contain non taxable items (no taxes appear to be applied but it still adds this $0.98 cents on the converted_amount).

I should also note that I searched the entire database for 0.96 thinking that it may be a configuration somewhere, but it turned up nothing.

beetree:

We have found that it has something to do with the taxes which are only applied to Canadians. This happens with the orders that contain non taxable items (no taxes appear to be applied but it still adds this $0.98 cents on the converted_amount).
So, how are all your tax settings configured?

DrByte:

So, how are all your tax settings configured?

Percentage based. I don't see any possibility for a flat rate or surcharge.

0 Taxable Goods BC PST 7%
0 Taxable Goods Canadian GST 5%

Do you have your shipping for Canada orders to be set as taxable? If you have a flat rate of $8.00 shipping, then $0.96 would become a flat rate additional amount, right?

DrByte:

Do you have your shipping for Canada orders to be set as taxable? If you have a flat rate of $8.00 shipping, then $0.96 would become a flat rate additional amount, right?

Hmm... I think you have it there. So what would be causing this? I have confirmed that it is not adding the tax on shipping during checkout, but tries to with the PayPal IPN . We have another store setup with the latest version with pretty much the same tax/shipping setup (with the exception of price) and it is working fine (it is applying the tax on shipping during checkout).

Here is the order for the OT modules, Shipping is configured to come before Tax.

Shipping ot_shipping 200
Sub-Total ot_subtotal 100
Tax ot_tax 300
Total ot_total 999

When I upgraded to the latest version I extracted the files from scratch and moved our theme over; so we can rule out any changes to core files.

Thanks for the help.