One way to sort/order access levels in the chart would be to add a column to the access_levels table in your databse (example s_order)
Then give each a number 1,2,3,4, ect in the order of importance
then in plan-comparision-chart.php
ORDER BY `s_order` ASC
to the existing query.
This is the manual way so, if you add any new access_levels you'll need too manually give it a sort number.