R7900 Nighthawk slow wifi with mesh ex8000

Hello all!   So I recently upgraded my Centurylink to 140/20MB/s.  My setup is their technicolor C2100T (wifi antennas disabled) to my Nighthawk X6 R7900 that is in "wireless access point" setting.  Then downstairs is my EX8000 to extend the network.  When hardwired directly to the R7900, I get the full 140/20.  But when I take my Surface Pro or Note9 around the hose, no matter where I am, upstairs or downstairs I get 65MBs down and 20 up.  I always get the full 20 up, but why is my down so slow, certain days it gets up to 70-75MB/s down but mainly it stays around 65.  My neighbor has the same connection as me, but he uses the ORBI mesh and everywhere you go in his home, you get the full 140/20.  

Firmware Version 
V1.0.3.8_10.0.37

please advise,

Thank you!