First, tell him that you are concerned that additional work was done
without your consent, and that you are going to have to run it by the
town board. Express to him that while you think he did a superior job as
the end result, there is a possibility it may have to be ripped out and
redone according to town specs, so you need tim to determine the next
step.

Presuming it looks as good as you say, it's really unlikely you'll need
to have it all redone. In this case, he is entitled to the top end of
the range he quoted.

If it has to be ripped out, he is probably liable for the damages you
incur. Consult a lawyer if this comes to pass.

I'm no lawyer so I can't advise you on your rights. Common sense tells
me that failing to get consent for changes in the work scope is a bad
business practice. Tell him that you might have agreed to some
additional charges had they been discussed with you in advance, so you
could plan for them, but in the end you have a written contract and no
change orders for him to use.

Marc