Hi everyone,

Sorry for my english, this is not my native langage  

I'm trying to create the following type of promotion, but I can't find the right setting : 

I would like to offer a 5% off if my customer buys a full box instead of product unity.

Exemple : 

I'm selling 1 unit of a product for 10€ but if the customer buys 4 of it (which make a box) he gets 5% off = 38€

>> If the customer buys 5 of it, he gets 5% off on 4 of them, and pays full price for the 5th, 6th & 7th ones = 48€

>> If the customer buys 8 of it, he gets 5% off on 8 on them

>> If the customer buys 9 of it, he gets 5% on the 8 of them & pays full price for the 10th,11th,12th & 13th ones. 

And so on ... 

Could you please help me on this issue ?

Thanks a lot !

Stéphanie