Suddenlink → [Connectivity] Will a modem upgrade resolve intermittent issues?

I've got a client who's been having problems with their Suddenlink HSI connection for months. This is a business account who has intermittent periods of high-latency and low bandwidth. They've got VoIP phones (not with Suddenlink) and when the cable drops the voice quality is horrible.

Calling Suddenlink support hasn't really gotten me anywhere. I figure I'd see what the community has to offer - if anything.

The call to Suddenlink today resulted in the agent remotely accessing and rebooting the modem. He then proceeded to tell me that the modem (Motorola Surfboard SB5101) didn't support DOCSIS 2.0 and that they've been having problems with older modems that do not support DOCSIS 2.0 or higher. I know they're running 3.0. I looked up the modem specifications and it supports 2.0 so I don't know why he told me this. I feel he was just trying to upsell me a cable modem/install service and not actually fix the problem. If upgrading the modem would resolve the problem, I would gladly recommend it.

Does anyone have any advice or been in a similar circumstance where upgrading the modem resolved the issue?

That's a yes/no sort of answer. Upgrading to Doc3 could help hide the issue in the fact that you are bonding multiple channels instead of using just 1. So an issue on one of the channels is less apparent