I think you have misunderstood..
Without the proposed one line change to /usr/sbin/vpnrouting.sh you do not honour custom names when stopping/starting the VPN Clients, but changing it doesn't break the code for any of the users that choose not to customise their VPN Client descriptions.
Your change implies that the routing table numbers will never change from 110-111-etc..., as that's what the grep is looking for. If Asus were to force a table number change in a future GPL change, or if a user wanted to change them, it would bring the opposite problem of the one you are facing. That's why I say that either method will have its drawbacks.