[Freeswitch-users] Best Practice - * Codes on some IP Phones

I am working with a Grandstream HT704 ATA device which has number special functions built in eg Do Not Disturb, Suppress Outgoing Caller ID Number, Enable/Disable Call waiting, - more than 20 in all. Unfortunately, one of the codes is *98 which pays back the extension number. In order for *98 to work for e-mail, I must disable all the call features. So my question- Is it generally considered best practice to disable the functionality on all phones, and provide it through the dial plan so that the codes will be consistent for all phones in the system, or let the phones provide the features, even if they may vary from phone to phone? Thanks for your time. William.