Replying to I totally just shat all up in my ski boots

Ok heres a question. I have to buy some boots, I chose some solomon foils because they're sicknasty and nice, and after skiing with shit boots for 4 years Im ready for some pleasure.

Heres the problem. I have to order them online, and im not sure which size to get. My local ski shop (who doesnt carry ski equipment in the summer) measured my foot and said I needed a 26.5 mondo, but the conversion chart on solomons website says that with a size 10 foot, (which I have), you need 28 mondo. Was the ski shop dude just saying that so I would buy one of the few boots he had left? What should I do?

And I need to get the boots in 14 days because Im leaving to travel, and I will be skiing.