I'm trying to make a simple API request using Google's Blogger API. Specifically, I'd like to get a list of posts for my blog and display 3 results at a time, allowing for paging forwards AND backwards. I'm having troubles getting a "previousPageToken" response back from the API and think I might be doing something wrong as their example they have does include this property when appropriate. This is the example I'm following and their proposed output. 
Below is the same url with the same blog id. The blog has hundreds of posts.
The request (I removed my API key):
https://www.googleapis.com/blogger/v3/blogs/2399953/posts?key=API-KEY&maxResults=3
The response:
"kind": "blogger#postList",
"nextPageToken": "CgkIAxiA7Pz3iCsQ0b2SAQ",
"items": [...
Okay fine that's page 1 so I don't expect a previous page token.
Next page request: https://www.googleapis.com/blogger/v3/blogs/2399953/posts?key=API-KEY&maxResults=3&pageToken=CgkIAxiA7Pz3iCsQ0b2SAQ
"kind": "blogger#postList",
"nextPageToken": "CgkIAxiAoM68xyoQ0b2SAQ"
"items": [...
Uh, what? We are on page two but the API didn't return a previous page token.
Am I querying incorrectly or misunderstanding something?