1. Post hub stats
2. Stop rebooting the hub
3. Monitor hub stats for connection time and sync speed for a few days
If the hub maintains connection and your speed still varies it is due to network congestion
The 32Mb guarantee is sync speed not download speed. I think when you finally load readable hub stats you'll be syncing at 32.
It won't be the speed that is causing Netflix to drop out, 27M is more than ample. However, if your line is suffering from an intermittent line fault that will cause the drop outs.
You need to monitor the line stats to see what is happening.