That they do; I'll buy a tube too. The more you buy at once, the cheaper it gets.They also offer discounts for bulk purchases. When I buy silver, I try to buy 100 coins at a time. The minimum I buy from them is a tube's worth - either 20 or 25 coins depending on the country of origin of the coins. I likely would not buy rounds or bars unless put out by a country's mint.
I'll buy rounds and bars that aren't government minted, but from known defunct mints (like Swiss of America; very collectible, but not usually a huge premium, but can be) and known dealers. And one or two of a design from a current mint; no discount for quantity, but nice designs that are hard to find at the big online dealers.