said by thecp:That's to waive installation costs. If you're willing to pay the high one time installation you can get business class without a contract. In my area it was $250 to get 'installation' (the cables were already there so basically the guy said, 'Here's a business cable modem') but it was contract free. If you're ok with the lowest tier it isn't that much more than residential. (now if you want higher speeds you really pay for it at 50Mbps/$189 and 100Mbps/$389 a month)
My friend in Sacramento, calif had to switch over to business class for comcast. In order to get the same pricing as when he had residential he had to sign for a 5 year contract. I'd rather stick a knife in my gut than be locked in for that long.