Hello, this problem still has no solution. We continue working the same. A possible "solution" is to configure the currency with 4 decimal places, that way the calculations have greater precision and it seems that the errors are corrected. The problem is that the prices in the BO and FO would be shown with 4 decimal places (and in our country only 2 decimal places are used).
This way of calculating taxes in prestashop is one of the disadvantages that I have found and that has not yet been improved.
In case I do not receive here a response that solves this problem, what I will do is report it as a bug on GitHub