It would make sense that brands would work well together - I recall Campy Centaur fitting onto a pair of Deda bars and making a really comfy perch, and I now have Pro bars with Shimano 10sp. Since they're made by the same company I'd expect them to work well together. But I also have 8sp shifters on the same Deda bars and they fit fine.
Guys who work in shops have to endure crushing boredom sitting round while everyone else is working their 9 to 5. They're probably one - upping each other seeing who can get away with the best BS for fun. They'll be dining out on that for months. About 3 years ago the only thing I managed to sell on a particularly quiet day was a bottle of chain oil for $11.90. That became a synonym for cr*ppy sales days and I still get grief for it.