POS, customer price group, affiliation

Hello,

can I find somewhere how Ax prioritize agreements beetween Trade Agreement per customer groups, affiliation group, channel group, in the POS.

I try to apply a discount retail on 2 affiliations groups. 
My customers are linked to one of the 2 affiliation group and one customer group.
It works, but only for one of the customer price group... 

in call center it's ok... I can't explain how POS select prices...