Medala Advanced Basic double pump question

prncebride

Does anyone else use the Medala advanced personal double pump machine?   

I pump for 10mins every 3hrs but I'm having trouble figuring out if I'm getting all i can from my pumping.  

The first phase: Stimulation Phase expresses in about 2mins but then switches over to the second phase: Expression Phase, I pump for the remaining 8mins on the Expression phase but nothing is expressed, and the machine won't let me switch back over to the first phase.  Am I staying on the machine long enough?  Is anyone else dealing with this also?