This is more or less easy to explain.
The Advanced MPU used to be called the Salience Turbo.
The main difference is that this fabric will support MPLS encapsulation and IPv6 and be capable of proxying those functions on behalf of non SD or EA linecards.
You will only ever need the advanced fabric if you are using SA and SC cards and require the above functions on those cards. Note that you will however experience centralized forwarding (what in Comware terms we call "proxying") to the MPU(s) rather than the distributed MPLS and IPV6 you would otherwise get with SD or EA linecards.
Everything else in those chassis is totally distributed to the line cards, similar to a DFC equipped Catalyst 6500 for those familiar with Cisco terminology.