diff --git a/htdocs/langs/en_US/margins.lang b/htdocs/langs/en_US/margins.lang
index d4545b8e75f..d52a387cfd2 100644
--- a/htdocs/langs/en_US/margins.lang
+++ b/htdocs/langs/en_US/margins.lang
@@ -36,7 +36,7 @@ CostPrice=Cost price
 UnitCharges=Unit charges
 Charges=Charges
 AgentContactType=Commercial agent contact type
-AgentContactTypeDetails=Define what contact type (linked on invoices) will be used for margin report per sale representative
+AgentContactTypeDetails=Define what contact type (linked on invoices) will be used for margin report per sale representative. Note that reading statistics on a contact is not reliable since in most cases the contact may not be defined explicitely on the invoices.
 rateMustBeNumeric=Rate must be a numeric value
 markRateShouldBeLesserThan100=Mark rate should be lower than 100
 ShowMarginInfos=Show margin infos