Account locked, clarification please

This did not happen today, but my account has been locked a number of times over the past month or two, especially the last week again. Each time I've been able to reset my password and get access.

I'm trying to understand what is triggering this so I can make any change if needed.

When last I called Customer Service, they suggested the lock came about because of a change in log-in behavior but could not tell me any details. They may have suggested it was an overseas attempt to access my account.

I have an authenticator and have run Kaspersky, Malwarebytes and Norton numerous times with and without WoW running and with the log-in screen open. I've never found anything 'bad' with those programs. And as far as I can remember, I've never used my battlenet account e-mail associated with anything else related to wow (i.e., fan sites, etc.)

What I'm wondering is whether these locks are triggered by my access from home (Verizon DSL) and a laptop I use at work (wireless Sprint). My home pc is within a mile of my laptop I use sometimes at work. It seems most all of the locks have occurred after I logged off at night to sleep and then later the next morning when I try to log on the laptop; usually the time between those log ins is on the order of 10 hours (and I live within a mile of work).

The only other time my log-in changed at all for many, many months (taking the laptop on a vacation, for instance) was this past weekend when my minor daughter who shares my account and lives with me accessed our account from the other side of the country (she was visiting her older brother over the weekend). I had no problem logging on to the same account right after she got off it. And in before anyone asks, although she's 10 she's quite savvy about the risks of Internet surfing and also daily ensures her pc is clean with Kaspersky and Malwarebytes.

If my locks are because of the switching between my home and work (again within a mile of each other) is there any way to stop such account locks? If the locks are coming as a result of attempted access from any other source (long distance U.S. or foreign) could you let me know that the solution may be for me to change my e-mail address on our battlenet account?