PS 8.1.7 Wrong Tax calculations - Specific prices set by percentage

[Jacek Es]

Hi,

I am struggling with Tax calculation on PS 8.1.7 which I believe to be a bug. I have tested all rounding modes and rounding types. The problem for me appears with the Round on each item type, Round up away from zero, when it is half way there (recommended) mode for products that have Specific prices set by percentage. Here is my scenario:

Currency decimal: 2
Round on each item
Round up away from zero, when it is half way there (recommended)
Specific prices set by percentage
Product base price: £0.30
Discount at 1000pcs: -31%
Tax: UK VAT  @ 20%

 

PrestaShop Order calculations:

The calculated VAT (20%) from £210 should be £42 but PrestaShop calculated it as £40. I can't figure it out why and how to change it.

 

The other 2 rounding types (Round on each line, Round on the total) have the tax calculations correct but the Item price with the discount applied is displayed wrong. It is displayed as £0.21 x 1000 = £207. For that reason I don't use these 2 rounding types:

Any idea how to resolve the wrong tax calculations on Round on each item option or change the display of item price for Round on each line, Round on the total options?

Regards,
Jacek