Discounted product price consistency

[Jacek Es]

Hi,

 

PrestaShop 8.1

How can I make the product specific price (discount by percentage) consistent throughout the shop and ordering process? Here my scenario and issue:

Product base price: £0.30
Specific price by % discount: -31% from 1000pcs
UK VAT @ 20%
Rounding mode: Round on the total
Currency decimal: 2

PrestaShop calculates the order as follows:

The issue comes from the product price with discount applied which is: £0.207.
£0.30 - £0.93 (31% discount) = £0.207

The shop's currency decimal is set to 2 and product discounted price is rounded to £0.21 but only on the display and invoice because the calculations are made from £0.207 which creates discrepancies.

We cannot have £0.21 * 1000 = £207

Two acceptable options would be either:

1. Display product discounted price with all decimals (without turning the entire shop into this):
£0.207 * 1000 = £207

or

2. Make the final calculations from the rounded product discounted price:
£0.21 * 1000 = £210

 

I have explored all rounding options and sadly non provides an acceptable solution. Rounding on each item have the display of initial calculations correct:
£0.21 * 1000 = £210
but in this option the tax is added to each item and rounded before the total is made which isn't desired:

Price after discount excl. VAT: £0.207, rounded to £0.21
20% VAT applied to each item: £0.21 * 0.20 = 0.042, rounded to £0.04
Item price, incl. VAT: £0.21 + £0.04 = £0.25
Total for 1000pcs: £0.25 * 1000 = £250

Anyone have ideas on how to keep the product discounted price the same in the order display, invoice and in the calculations?

Thanks