SV8100 and 9100 or not identical when it comes to licensing, there is big difference.
On the SV9100 If you have 20 extension and 10 licenses and you need mailboxes for extensions 101, 102 105, 108, 112, 114, 115, 117, 118 and 119
You assign 101 to mailbox 1, 102 mailbox 2, 105 mailbox 3, 108 mailbox 4, 112 mailbox 5, 114 mailbox 6, 115 mailbox 7, 117 mailbox 8, 118 mailbox 9 and 119 mailbox 10
If you have 5 voicemail to email licenses they can be assign to any of the 10 listed.
SV8100 you could scatter them around.
