Trying to get the insurance to work reasonably well for both USPS and UPS rates since I use UPS in the U.S. and USPS to other countries.

USPS with rate chart selected works great of course but then UPS rate is significantly higher than actual UPS rates because they are using USPS higher insurance rates.

I've been working with percentages to get them both to be at least close to actual cost but when I use percentage I get this message on checkout step 3:

Warning: Missing argument 2 for zen_add_tax() in ../zencart/includes/functions/functions_taxes.php on line 94

Line 94 reads (along with comment above):
////
// Add tax to a products price based on whether we are displaying tax "in" the price
function zen_add_tax($price, $tax) {

However, tax appears to be adding correctly, or not showing as it should in every place but my state but message always shows regardless.

Anyone run across this before or figured out a way to have the module work for both USPS and UPS depending on option provided at checkout?

In my case shipping method happens automatically based on U.S./non-U.S. and no choice is given.

Thanks.