Hello
Currently we use old marketing system in our solution. As I know the legacy promotion system will be completely replaced by new the marketing system.
So I started to research how the new promotion system works. My approach is very simple: I create configuration on one site with old promotion system and the same promotion configuration with new discounts on another site. After that I compare results. And I see slightly different values.
For example we have two promotions applied to our cart: item level and order level.
Old system shows the following calculation: item promotion 3.00, total discount 4.00, subtotal 30.00
New promotion system shows the following calculation: item promotion 2.99, total discount 3.99, subtotal 30.01
I can assume that new workflow or default promotion engine implementation uses intermediate rounding in calculation which leads to loss of accuracy.
I suppose that such behaviour can be handled by custom implementation of promotion engine but I am afraid that code responsible for this calculation is very deep on marketing system.
Could you please comment this behaviour or advice any possible solution.