I have an SB8200 on xfinity/comcast.  I have had it for 5 years or longer. I was on the 400/12 plan, and on Sunday 15 October I upgraded to the 800/20 plan.  I did it online.  Everything went well, and for about 24 hours all was well.  Then, my download speeds dropped to to 18MBps.  I called xfinity, and they ran their remote diagnostics, and said there was a problem which needed escalated to the ‘speed tier network”, and was told it would take a couple of hours and that they would contact me when finished.  They contacted me about 2 hours later, said it should be fixed, but nothing changed.  They have me scheduled for a tech visit on Thursday.  Nothing else in my network has changed, just the bump in speed.  Would It help to call xfinity and have them reprovision my modem?  How safe is it for them to do so?  I have read stories of people trying to reprovision their modem, but after it is remove from their end, it will not reprovision because it is ‘locked’ to an account.  Here is the info on the modem: 

Hardware Version             6

Software Version              AB01.02.053.05_051921_193.0A.NSH 

Is it advisable to call xfinity and request a reprovision?