Visa requires provisional by business day 5, Reg E requires it by business day 10. You can always do more than Reg, but never less.
Visa rules are a contract between your bank and Visa, Reg E implements a law.
I don't recall that Visa requires the notice in writing? (I am asking as much as anything, I haven't had to apply Visa rules.)
My opinions are not necessarily my employers.
Rules and Regs minus Relationships equals Resentment and Rebellion. John Maxwell