[Koha] bug in Acquisition module, regarding VAT management ?

[Mathieu Saby]

Hello
We think we have found a bug in Acquisition module, regarding VAT 
management, but we want to be sure.

Let's take a book whose *recommended retail price excluding tax *is 39 
euros.
On the vendor's website, I import the record for this book in iso2709
In the record (UNIMARC), the price is in 010$d after the ISBN. So, I 
found : $d39.00 EUR
I stage this record in Koha with Stage Marc Records Tools.

In Acquisition module, I create a vendor with:
- List item price includes tax: Yes
- Invoice item price includes tax: Yes
- Discount: 9.0000 %
- Tax rate: 5.5%

I create a new basket for this vendor.
I fill this basket with my stage record.

I think I should have for the command line in this basket :
- RRP tax included : 39 euros
- Ecost tax included : 39 euros - 3,51 euros = 35,49 euros
- RRP tax excluded : 39*100/105.5 = 36,96 euros
- Ecost tax excluded : 35,49*100/105.5 = 33,63 euros

*BUT instead I see the following values : *
- RRP tax included : 42.86 euros
- Ecost tax included : 39 euros
- RRP tax excluded : 40,63
- Ecost tax excluded : 36,97

So, Koha considered the "39 euros" value in my record as a Ecost price. 
I dont think it is normal, as as chose "List item price includes tax: 
Yes" in vendor record.
Do you agree with me?

-- 
Mathieu Saby
Service d'Informatique Documentaire
Service Commun de la Documentation
Université Rennes 2
Téléphone : 02 99 14 12 65
Courriel : mathieu.saby at univ-rennes2.fr