[tomascot]

What could cause that that you mention on point 2.

Are they "caching" responses or that offer is tailored to your user/cookie?

[callmeed]

My guess is either (a) they're pulling the original price from a DOM element and not checking if there's also a sale price (most sites with sales prices will show the original and the new price), or (b) looking for schema.org product data and not looking at the correct item [0].

[0] http://schema.org/Product