for a moment didn't catch this sentence in the quotes lol, in addition to Puwaha's explaination:

A Pool Group in AM is something you setup under Options -> Pools, where you define individual pools which has profit information from Whattomine (default) or Coinwarz and can be used with all your miners, External, Managed and Managed Profit. To use them for Managed Profit Miner when you have many, many individual pools setup already, you need to create a pool group under Options -> Pools -> Pool Groups tab. These pools don't have to came from the same pool owners, they can be from Suprnova, Nanopool to any available pools out there really.

MPH, Yiimp based pools are Multipools, they are like...Groups of Pools...rather than Pool Groups, they run their own metrics within multiple algos (and many coins within some algos) that they provide and gauge the profit within their own pools. They have their own switching rules even if you don't use AM, MPM or the likes, some switches between algos, some only between coins of the same algo (Yiimp) and MPH kind of does both to a certain extent.

what AM does is that it combines both Multipools' and non-Multipools' metrics and allows profit switching between pool providers so you get a lot more flexibility but also have your hashrate and earnings more scattered which can be more of a negative impact for casual low hashrate miners since payout threshold then would take longer to achieve.

Hope this doesn't make it more confusing.