Welcome to FT,
rockym.
Two recent changes might have contributed to your predicament.
Firstly, the exit row is now uniformly numbered as row 12 on all Airbus and E190 aircraft. Secondly, F9 recently started charging a fee for exit row seating, classifying the row the same as STRETCH.
STRETCH and exit row may be booked at no charge by Summit members, but Ascent members only will have free access at time of check-in or at gate.
You can refer to previous thread
http://www.flyertalk.com/forum/front...h-seats-5.html, starting with post #69 for further info.
Updated seat maps can be viewed at
http://www.frontierairlines.com/fron...y-info/A319.do. As you will notice, some aircraft no longer even have a row 10, due to the renumbering of exit row.