I just posted this over at Scott's Table forum for you:
Make sure you don't have any seats "locked" (on the tables tab, there is a "lock" button, click that and clear all locks).
On the settings tab for tables, make sure player disparity is set to "1".
Also, make sure on the settings tab, that the box is marked "move players as close to seat 1 as possible"
This last maneuver will likely fix your problem alone.
unseat all players,
if need be, you can "make seat unavailable" for seats 8, 9, and 10. At least when you do your initial seating, then you can make them available again. You shouldn't have to do this.
then reseat the players.
If it still doesn't work (should), you could always manually move the players next to one another and also just manually move players to even out the tables (by dragging and dropping players to a new seat at a different table or at the same table).
You should not have to do the manual thing. I have the latest TD and it will seat 14 players as 7 & 7 at 2 tables with all players seated at seats 1-7. I just tried it.