| | Hi jgroove,
Excellent question! There are indeed many different ways to describe the various levels/states of concentration.
I don't know much about B. Alan Wallace's tradition, but I know that there are a variety of ways in which the stages of shamatha and jhana are understood within the Theravada tradition alone. It's safe to safe that there is no Universal consensus on this matter.
To get a feel for the differences within the Theravada tradition, listen to the to Buddhist Geeks episodes with Richard Shankman:
1.) The Power of Samadhi --> http://bit.ly/1PlTbe 2.) Different Types of Jhana: Sutta, Vishudimagga, & Vipassana --> http://bit.ly/Y4Vmt
I think his hypothesis can be applied across other Buddhist traditions as well.
I hope this helps :-D
~Jackson |