renewing onecare

Even though i know Microsoft Onecare is going sometime in the new year, I recommended my dad to renew anyway as he was happy with the product and comfortable using it.  So rather than do the online billing at £37 I suggested he buy a brand new copy at somewhat less from Amazon.co.uk  (around £24 ISTR)

Anyway as one of my regular jobs whilst visiting is sorting out the family pc problems he asked me to update his onecare with the new one.  So put the disk in and got a wonderful error message 0006-80004005 and bascially some text that said I would couldn't have 2 copies of Onecare on the same machine and I would have to uninstall the current one and then re-install.  I feared doing this would loose all the settings and maybe screw up a whole bunch of other things and the get more help option  was not. So after a bit of research I came across this https://www.vistax64.com/live-onecare/139278-retail-box-version.html on the Vista x64 forums that told me how to fix the problem (copied below)

Don't reinstall OneCare.
Purchase the retail box copy and then go to https://billing.microsoft.com
Sign in with the subscription LiveID (Help/About in OneCare will show you the
Subscription ID)
Select the renew link in the billing entry for OneCare.
Select the option to renew with a retail PIN or token.
Follow the wizard for this and proceed with renewal. You can do this at any
time, not just when you are due for renewal.
It can take up to 24 hours to reflect the new subscription status in OneCare.

But what stumped me was the term Retail Pin or Token, now going through the billing process it was clear it was asking for what I think is more commonly termed a product key... So why is it called a Retail Pin or Token  and not at least adding or Product Key (as it is actually called on the box)

As someone once sang Confused you will be

Rob