Not sure what the issue is. You have some issues if you had to walk away before you "laid into the guy".
People on here don't know the difference between RBA's, RDA's, Atties, Clearos, Tanks, Carts, Drippers, Bridgeless you name it. At all mall Kiosk, I do not expect the guy to know anything. They are basically a teenager that signs up to do Kiosk work... he/she may do sunglasses one day, greeting cards another. They are basically just a body.
Do you go into Walmart and expect everyone in Walmart to know everything about every product?
So he got the mah rating mixed up.. Quick check of the package shoudl clear that up. I have been into specialty stores with experts that mix things up but eventually after a conversation they get it right. Was in Verizon (not a kiosk or mall - I despise malls) getting a iphone for my daughter.. she wanted the 5S instead of the 6. The guy kept telling me the price was 199 for the 5S. The sign said 99. I knew better and knew by the end of the conversation we would get it right. SO before I corrected him I asked if they sell more 6s than 5S.. He said that is all we sell. There ya go explainable and I did correct him at the end and he said "Sorry you are right." No worries and definitely not a reason for me through a hissy fit.