customer uses coupon, sales tax disappears!

Ok here is a weird one...

My business is in Ohio, so I charge sales tax to customer who's billing address is in Ohio (doesn't come up often). All is well, sales tax is charged correctly in step two until coupon is applied...then sales tax disappears. I also noticed while trying to correct/troubleshoot this order, that if I enter the coupon code and no payment method, it goes on to 3 anyway.

Am I missing a setting or something? Or is this a bug?

More info: here are the totals with the before coupon amounts:

$227.82
Sub-Total:

$0.00
Shipping:

$14.86
Ohio Sales Tax::

$242.68
Total:

Now here is where is gets weird...after applying the discount code for 10% off:

$227.82
Sub-Total:

$0.00
Shipping:

-$24.27
Discount Coupon: usefororderfix :

$169.13
Total:

First notice that 227.82-24.27 is not 169.13...it should be 203.55 AND the tax is missing. How can I fix this. The only other thing I could think to try was to change the % coupon to a fixed amount, but it did the same thing. Appears that it is something with the calculation that is wonky not the coupon?

Not sure why this works, but here is how I got it fixed.

Under modules/order total/discount coupon, I set all values to "true" (not what I thought it should be, but it worked) except recalculate tax and tax class, which I set to none.

Hi, I was having a similar problem. I used the solution above and it seems like it's working. However, I still don't understand why this solution works.

In addition to the issues above, the wrong payment method was showing up in the admin. Instead of Paypal or Credit Card, I saw "Payment Method: Gift Certificate/Coupon". In addition, if the payment method was Paypal, the user was not directed to Paypal upon completing the order.

However, these problems only seemed to happen when there were multiple items in the cart. When I only had one item, the tax showed up, the calculations looked correct, and the credit card numbers showed up for the order payment method in the admin. I have not been able to isolate if there were particular products that were causing the problem.

Before I changed it to the settings above, my order discount module was set to:

This module is installed
true

Sort Order
280

Include Shipping
false

Include Tax
false

Re-calculate Tax
Standard

Tax Class

Could the problem have had something to do with the sort order of my order total modules? It is:
Sub-Total
Shipping
Discount Coupon
Tax
Low Order Fee
Gift Certificates
Total

Does anyone know why this was happening, and why this solution worked?

It seems that recalculating the tax on the coupon is causing part of my problem. If I have multiple items in the cart and I have recalculate tax set to standard, the tax disappears and never shows up again. If I only have one item, everything works fine.

This is not what was causing the wrong payment method to show up, however.

Does anyone have any idea how to fix this?