Frustration -- Having to dial *18 when roaming

I live in CT and have a Motorola v710 and one of the "America's Choice"
national plans from Verizon. When I travel outside my home area -- even
if I am in Verizon territory -- I can dial out and receive voice mail
messages, but I can't receive incoming calls... unless I dial *18. I
have read what I could find online (here and elsewhere) on this topic,
but I am puzzled (and frustrated) because...

... during a trip to OH this week, a colleague who I have been
travelling with (and who has a Motorola v60 from Verizon with the same
plan) has not had the same problem

... on previous trips in New England, NY, and New Jersey, my wife has
not had the same problem with her v710 and identical plan from Verizon

and
... I had the same problem with an earlier LG XV6000 ... but not with
earlier Motorola, Kyocera, and Nokia phones I had.

... two Verizon telephone technical support people told me that
everything was "normal" (they both thought that having to dial *18
every 30 minutes while driving zone to zone on a long car trip to make
sure I stayed connected wasn't a problem).

... two other Verizon telephone technical support people told me that
my phone must be defective and that I should bring it to my local store
tech support department

... my local store tech support department said that updating my
roaming list would solve the problem (even though I had already done
that multiple times).

My phone is set to "Automatic B".

Thanks in advance for any thoughts, tips, fixes etc.


--
jcwCT