CISCO 3640 Bonding DSL MLPPP

I've setup MLPPP in my cisco router connecting through DSL.  The problem I'm having is the full use of the PIPE.  I'm using MLPPP to bond 2 DSL channels.  Each channel is 6mb x 512k.  So in theory I should have 12mb x 1mb.  

On the customer end is a Cisco 3640 router that connects to a local DSLAM that then connects to an ATM cloud which terminates into a Cisco 7206vxr.  On both end's of the connection I see the following:
Interface    User         Mode              Idle             Peer Address
Vi1                             PPPoE             00:00:03
Vi2                             MLP Bundle    00:00:25    10.10.10.xxx
Vi3                             PPPoE             00:00:03

At my core router 7206vxr I see the following:
Interface     User    Mode               Idle             Peer Address
Vi21            user1   PPPoVPDN      00:00:01
Vi22            user1   PPPoVPDN      00:00:10
Vi23            user1   MLP Bundle     00:00:01  10.10.10.xxx

When I preform a speed test at speedtest.net or speakeasy.net/speedtest my results are as follows
On the down 5.2mb (not 12mb)
But on the upload I can hit almost the full speed of the bonded MLPPP circuit.
On the up .9mb (not 1.0mb)

I've attached my config for the cisco 3640.  Items are commented out such as VPN and user info.

I need to be able to hit the full down.  My customer doesn't believe they have a 12mb pipe.  Please any help that can help me fix this is greatly apprecaited.