Re:

Leave your office number as the primary. Set your office phone to
automatically forward messages that are not played in x minutes to your
cell phone.
Secondary number is rarely, if ever used. I suppose if your office phone
voice message said "The dirty rotten scoundrel has been fired - don't
leave a message." IBM might look at the secondary.

I've had messages left on my voice mail over the weekend "Your system
reported a disk drive gone bad, I'll try calling back on Monday."

Rob Berendt