Hey Ang! Shakespeare and phone book, hey?! Well at least they're both popular!
On the note of "warranty period" versus "expiration", that may be a localisation issue. Here in Australia, they mean different things. Warranty period is the period after which you're on your own if the product dies. Expiration is not often used (in this context) but would typically mean "use-by date", I believe.
For the "big flashy offices..." example, I agree that I could have used "inside", but it just doesn't have the same feel to it, for me. There's more friction in the word "inside". "within" is fast and smooth (no sibilants), and that's exactly what I was aiming for there.
I agree the final example is a little odd. It didn't sound that ood in context, I promise. But odd, nonetheless!