You are correct to point that out... with the correction that the .10c is for the CQG execution route, not the platform. It's a CQG fee regardless of platform, free or paid: at least at AMP.
Here's the next comparable set-up at Amp...
Looks like .37 per side is best you can get with their current set-up. It gets more expensive from there if you choose platforms and feeds like TT and Rithmic.