You just need to buy you AnyConnect Premium licenses for the phones, plus a single
AnyConnect for Cisco VPN Phone license. The Cisco Phone VPN license is just a simple enable license, rather than a counted license.
This is what my ASA looks like with a "sh ver"
...
AnyConnect Premium Peers : 50 perpetual
AnyConnect Essentials : Disabled perpetual
Other VPN Peers : 750 perpetual
Total VPN Peers : 750 perpetual
Shared License : Disabled perpetual
AnyConnect for Mobile : Disabled perpetual
AnyConnect for Cisco VPN Phone : Enabled perpetual
...
GTG
Please rate all helpful posts.