Didn't the article say some floors require keys for different offices and sometimes filing cabinets.
That implies every floor is different which matches what you are saying.
Most of the stories that have come out felt like they were the image Apple wanted to give. It started with Apple going after missing iphone that was left at a bar. We've heard those working on latest design for the next iphone were sequestered away from the rest of the company. I've always thought it was marketing spin and I'm glad we have an ex-apple employee confirming this. Back in the 'Lisa' days Apple did split and silo divisions, Apple did closely guard new iPhone designs with very few leaks happening but the rest of the mythology is more marketing.