Frustrations with 6141 modem at night / peak hours - Roanoke, VA Market

To whom it may concern,

I am getting great speeds on my modem (110 - 130 mbps)  early in the morning and during the day, but at night (after about 7PM) speeds drop to around 5-15mbps. I've had several techs out to the house, they have replaced lines all the way to the street, even replaced the node at the street, but I'm still having issues.

Things seemed very promising with the last technician, but I haven't heard from him in a few days. It's very possible he might be working to fix the issue (he suspected it might be on something with the service delivered to my area, not at my house), but he had mentioned that a firmware update might prove useful. I've seen where other users have request a firmware update on this forum, could I request a firmware update? What information do I need to provide?

Thanks so much.