Where is the Sub Account Format changed?


Background
Just did a modification to the COA where we added a new segment to the front of the Account number. Now we are trying to get the new segments to appear in Project. The New Segment is Segment 1 in the COA and the names appearing in the second picture are how it appears now, but the option to choose more than two segments is not there.
What I need is to know What Table, What field (s) need to be updated so that we can get to the end result
In the Pre-converted system
Segment 1 represented the City where the work is going on
Segment 2 identified the professional services / displine engaged in the project
None of the values in those segments will need to change.
What we are trying to add - in all cases - is a NEW SEGMENT 1 - that is populated with a 2
So that
New Seg 1 is populated with 2
Old Seg 1 becomes New Seg 2 with same values
Old Seg 2 becomes New Seg 3 with same values
Therefore pre conversion the Sub Account Format looked like
20-01-####
Now with the new COA format we need the Sub Account Format to look like
2-20-01-####