I just added an additional trunk to my Sip Station Account, when I added the third one I expected to see the dashboard update to show the new trunk, however it did not.
I have confirmed that the trunk is there and I can use it, we did a test to three outside lines at once. 
That is not how trunks work. You will always have two trunks from SIPStation. Even if you ordered 20 trunks.
In freepbx think of “trunks” like servers. You have two trunks because you are connected to two trunking servers. A primary and a failover.
On the sipstation side a trunk is 1 inbound and 1 outbound call. So with 20 trunks I’d have 20 inbound and 20 outbound calls at the same time.
got it, thanks for the quick reply!