Shopping cart Subtotal and Total calculation error - v 1.80

Hi,

I am getting the following error on the shopping cart calcualtions:

Sub-Total:  £1.17 (GBP) excl tax  
Shipping:  £0.00 (GBP) excl tax  
Tax 17.5%:  £0.20 (GBP)  
Total:  £1.38 (GBP)  

Here is the error - The Total should be 1.37 and not 1.38.

Some background info on the setup. Default site currenty is selected as BGN
The cart currency selected is GBP. There is 1 product in the cart at unit price 3 BGN (or 1.30 GBP as displayed)
Discount coupon for 10% is applied and that's why the cart price is 1.17. Tax rate is 17.5%

Exchange rates are set as:
BGN to EUR rate is 1.9558
GBP to EUR rate is 0.8489

Please let me know if there is anything to change in the setup or it's a bug?

Thanks,
Antoan

The same is happening with US dollars as well.  I currently have a client that is experiencing it on seemingly random orders.  It seems to be a rounding error somewhere, but not sure where.  Has this bug been reported on CodePlex yet?  I couldn't find one.

Antoan wrote: