authorize.net echeck vs local tax mod

I am running Zencart 1.3.8 with several add-ons.
I am using a local tax add-on to calculate and include city/county taxes. I have been using this add-on for a while with the Authorize.net AIM module with no problem.

I installed the Authorize.net echeck payment module and I am testing it. On the checkout confirmation page, the order total below the shopping cart is correct - the local tax is shown correctly. Also, the order total amount sent to Authorize.net is correct.

However, in the section 'Authorization Notice', the total shown does not include the local tax.

Evidently, the calculation of the order total for the Authorization Notice is not the same as the calculation for the actual amount sent to Authorize.net. Is this a bug? Is there some code that needs to be added to any add-on that affects the order total?

Thank you.