hi everyone and especially srturner47!
let me start with thanking you for putting so much work in this neat module.
i'm very sorry to inform you that i think i stumbled over another bug which makes it hard to use this module for my purposes. i set up a shop, where i need to have products that are taxed with 2 different rates. so most of the products are taxed with 7%, while shipping and some products are taxed with 19% (yes, i'm from ger ).
as long as i do not edit an order, taxes are calculated fine, heres an example:

1 x product1 7% €52.00
1 x product2 19% €6.80
subtotal €58.80
shipping €7.00
7% €3.40
19% €2.21
order total €65.80

when i open this order up for editing, everything looks fine, but as soon as i update it (even when nothing was changed), something strange happens:

1 x product1 7% €48.60
1 x product2 19% €5.71
subtotal €54.31
shipping 19% €7.00
7% €5.82
19% €5.82
order total €72.94

i hardcoded the shipping tax rate like you proposed some pages ago. as you can see, the total tax gets duplicated and added twice. also the 7€ shipping is a gross value already, but the tax gets calculated once more.
5.82= (5.71+7.00)/19*100+48.6/7*100

any help regarding this problem would be very appreciated, even the slightest poke in the right direction ;)

thanks a lot