Tax rounding issue, one cent off, PayPal Pro error 15008

[dacrosby]

I'm using Joomla's 2.5, running VM 2.5 and encountered what appears to be a tax rounding issue with PayPal Pro/. API. On some orders, the cart displays the correct order total, e.g. $34.68, but when I go to checkout PayPal gives me back error 15008 saying the total in the cart doesn't match the total and refuses the transaction. The error transaction log gives an "AMT" parameter back with the error set to $34.67 - one cent off from what it should be.

I've disabled my template, all 3rd party plugins and have now updated (on a duplicated dev site) to VM 3.0 and am having the same issue.

It's not on all order values and I've only been able to produce the error with a per item tax (in my case, 6.875%). That is, with the same four items in my cart the order fails when tax is applied but goes through when I disable tax.

Additionally, the identical order is processed without issue through PayPal Standard - the issue seems to only be when checking out with a credit card sent to PayPal Pro. To reiterate, most orders are processed using PayPal Pro without a problem so I'm certain it's not a general setup issue, it's just occasionally someone hits a "magic" item combination that seems to round the number incorrectly in PayPal Pro.

I've seen other mentions of this and similar issues in the forums but mostly from 5-7 years ago and generally not with an actual fix. Anybody have any ideas of what this is, or what I can check?

[Studio 42]

Hi,
In payapl pro you have the details from your product.
If you check in config>price . Round only display, then i think you have the error(or perhaps uncheking it) Try the 2 solutions, one should work ok on paypal Pro

Greets,
Patrick

[dacrosby]

Patrick,

I'm not sure where you mean. In PayPal (on their website), the only API information is the login credentials, there's no setting nor product details. I'm looking under Profile -> Selling Tools -> API access. Is there somewhere else?

In Joomla, the PayPal payment method settings are about the same; there's nothing relating to rounding settings that I see. Where would it be?

[Studio 42]

The setting is in VIrtuemart config