Upstream power issue - what should I see at edge of house?

Hi I have a netgear C3700 docsis 3.0 router that has been having intermittent issues with upstream signal lock.

When I look at the signal in it's present location, the upstream power is showing as 50-54dBmV across the 4 channels.  If I disconnect and move the router to a direct connection to the line from the street, I see 38.8 dbmV for 3 channels and 44.8 dBmV for the 4th channel (i.e., 10dBmV difference).  I do have 2 splitters along the path from the edge of the house to the desired location.

So I think what is happening is I'm right at the edge of signal strength.  Is it reasonable that the direct signal needs to be 44.8dBmV right at the edge of the house (i.e., outside)?  I would have thought ComCast would need more like 35-38dBmV allowing me 2-3 splits to get to my location.  What should I expect?  

Thanks