What are tier 1b and 2b?

In the App Store Pricing Matrix document, Note states "Price tiers 1b and 2b are for Newsstand In-App Purchases only. Tier 1b is identical to Tier 1 and Tier 2b is identical to Tier 2."

And yet if you look, Teir 1b, 2b is no where to be found.

There are Tier 1, Teir 2, Alternate Tier A, Alternate Tier B, Alternate Tier 1, and Alternate Tier 2.

So, which are Tier 1b, 2b?

From the look of it, it seems to be Alternate Tier 1, Alternate Tier 2. Can someone confirm please? Thanx!