I'm using the Businesses & Hobbies EP with the Small Business/Residential Business lot. If I load from the 'travel' screen, I get the expected option to visit the household, or visit the business as a customer. However, if I load through other means [including (1) Click on building while loaded into the neighborhood, (2) Leave a sim on a Small Biz lot, navigate away to another lot/household/menu, then load the original sim at the Small Biz lot], it loads into the lot but the business is closed, and there's no "knock on door" or other residential interactions. There is the "Switch control to this household" option. I can also interact with items in the Small Biz areas without paying (i.e. use skill objects, read books, etc) but the business-related options (such as attending classes) are not there, and employees are not spawned.
Edit By Crinrict: Added Tag to Title, Adjusted Title
