It sounds like he is doing the FCP Euro oil change kits with Liqui-Moly, which in that case you only pay for shipping the old oil back to them and get a full refund. The entire oil change can be had for just the cost of shipping, which for me is around $15. I did a UOA of Castrol 0w40 and Liqui-Moly Molygen 5w40 and the wear numbers were almost identical.To me Liquimoly is hardcore advertising. Their oil is nothing special but it will get the job done in which it is intended to do so. I’ve seen M1, PP, Castrol (euro approved all of them) have the same if not better wear numbers for a much much cheaper price.
I’d stick to what you’re using as long as it meets specs.