I'm not sure I'm following the discussion. Is the question one of disclosing liability under zero liability rules or using the term "gross" in the negligence section?
As to liability, refer to 1005.7(b)(1) which describes, in part, the initial disclosures you must make under Reg E. "A summary of the consumer's liability, under Sec. 1005.6 or under state or
other applicable law or agreement, for unauthorized electronic fund transfers" I've bolded why your Visa terms would apply as they are not law, but an agreement you have between the bank, Visa and the consumer.
And the .6 reference is to 1005.6(b)(6) which states "If state law or an agreement between the consumer and the financial institution imposes less liability than is provided by this section, the consumer's liability shall not exceed the amount imposed under the state law or agreement." so again we have "agreement" restrictions that should be disclosed.
My solution was to add zero as a tier of liability.
If the question is about using the "grossly negligent" standard, lets explore this.
First, the Visa Core Rules,
https://usa.visa.com/dam/VCOM/download/about-visa/visa-rules-public.pdf, removed the word "gross", see page CR-43, last April. (Rules section 1.4.6.1)
Next, what is the definitional difference between "grossly negligent" and "negligent?" I don't believe Visa defines this but I welcome Brian's comments. It would seem gross negligence is a really, really dumb thing, and negligent is just really dumb. Does your state define this? Regardless of how it is defined, I assume (it's a dangerous thing to do) that gross negligence is one standard, and negligence is a lower standard. This means that the consumer (Reg E) will have more liability for doing something really, really dumb which they didn't have before. This means liability is increasing and Reg E requires a change in terms notice if liability increases.
So, if your bank will use a lower standard of liability, changing to "negligent" vs "gross negligence" then under Reg E a 21 day notice is required. If your bank opts to enforce the rules as they have been, you are not making a change and no notice is required.
If you review claims for the last 6 to 12 months, how many times would you have reverted from zero liability using gross negligence to say $50 liability under Reg E's tier one or a greater liability amount? If you look and estimate the bank would have not paid $100 on claims, that's a pretty low savings. If your analysis says we would have held the customers to more liability, saving the bank $10,000, that's pretty high. If you say there would be no change in your claims liability, it's moot. Now you can judge if making this change would be cost effective by itself, or do we want to schedule this change with another Reg E (21 day notice) or Reg DD (30 day notice) change you will make at year end, as an example, when fees may go up on deposit accounts, or do you want to change it all.