Multi-Device Security & Backup Bundle

I currently have the Internet Security Suite/up to 6 computers - with 3 Desktop PC's and 3 Laptops.

Looking at changing to the 'Multi-Device Security & Backup Bundle 50GB' bundle which is same price (at least for 12 months) that has "Unlimited* protection for all your devices"

But the note says:

      *Subject to limitation on reasonable use and purpose of the product.

Does anyone know if this will cover existing 6 PC's and a couple of tablets?

What does Verizon consider as "reasonable use"?

Also is it easy to change the plans? Assuming its the same security software on the PC's.

Thanks,

Mark