random slowness on Comcast fiber in ALB, NM

We are seeing random slowness during the day on our fiber connection.  D/U are in the 300/30 range but then will slow down to 58/33 or 63/33 speeds.  When the internet is slow, we're seeing traceroutes times like these:

2     2 ms     2 ms     2 ms  50-251-14-190-static.hfc.comcastbusiness.net [50.251.14.190]

  3    33 ms    24 ms    43 ms  100.92.127.130

  4    10 ms    10 ms    13 ms  68.86.183.93

  5    17 ms    15 ms    13 ms  68.85.65.89

  6    11 ms    11 ms    18 ms  96.108.43.101

  7    20 ms    17 ms    18 ms  be-36841-cs04.1601milehigh.co.ibone.comcast.net [96.110.44.29]

  8    24 ms    20 ms    18 ms  be-1413-cr13.1601milehigh.co.ibone.comcast.net [96.110.39.110]

  9    18 ms    25 ms    18 ms  be-304-cr13.champa.co.ibone.comcast.net [96.110.36.205]

10    25 ms    17 ms    18 ms  be-1413-cs04.champa.co.ibone.comcast.net [96.110.37.237]

11    19 ms    19 ms    17 ms  be-3412-pe12.910fifteenth.co.ibone.comcast.net [96.110.33.142]

12    18 ms    22 ms    26 ms  4.68.74.13

When the internet is running fast, traceroute times are:

 2     2 ms     2 ms     2 ms  50-251-14-190-static.hfc.comcastbusiness.net [50.251.14.190]
  3    33 ms    24 ms    43 ms  100.92.127.130
  4    10 ms    10 ms    13 ms  68.86.183.93
  5    17 ms    15 ms    13 ms  68.85.65.89
  6    11 ms    11 ms    18 ms  96.108.43.101
  7    20 ms    17 ms    18 ms  be-36841-cs04.1601milehigh.co.ibone.comcast.net [96.110.44.29]
  8    24 ms    20 ms    18 ms  be-1413-cr13.1601milehigh.co.ibone.comcast.net [96.110.39.110]
  9    18 ms    25 ms    18 ms  be-304-cr13.champa.co.ibone.comcast.net [96.110.36.205]
10    25 ms    17 ms    18 ms  be-1413-cs04.champa.co.ibone.comcast.net [96.110.37.237]
11    19 ms    19 ms    17 ms  be-3412-pe12.910fifteenth.co.ibone.comcast.net [96.110.33.142]
12    18 ms    22 ms    26 ms  4.68.74.13

Have opened a couple of support tickets and was told they would be escalated to Level II, but they keep getting closed without any update from Comcast Support.  We worked with a tech to power-cycle the modem last time and he was going to escalate - but the ticket just got closed.  The speed changes are random but seem to be within the Comcast network?  

Any help would be appreciated, off and on now for 5 weeks.