I don't know exactly what fees you're referring to. If I knew, it might help me answer your question.
However, I can assure you that we always deal with our suppliers transparently when it comes to fees. If there are fee increases, they're always justified. We give them plenty of advance notice so that they can prepare for them. These fee increases are often justified by our own cost increases. I'm not aware of a 3–6% fee increase. I don't know where that came from.
Some fees also vary depending on whether they're calculated by the case or by weight. This can have an impact. If someone delivers more goods to us, their fees will be higher because they're based on the number of units.