There are NOT multiple plans of "consumer" AppleCare. All iMac, Power Mac and Mac Pro AppleCare plans offer on-site (if you are located within 50 miles of an Apple Service Provider) and carry-in Apple Store/Service Provider support.
PowerBook, iBook, MacBook and MacBook Pro AppleCare plans offer mail-in or carry-in Apple Store/Service Provider support.
M8853LL/B appears to be an older, retail version of AppleCare. This happens periodically as Apple updates the packaging and included TechTool disc. As far as your warranty is concerned, there is no difference.
By the way, TechTool is also available for APP members via download on Apple's Web site.