First of all, the strips used in the old Insulinx meter are Freestyle Lite strips here in Canada. They are about $80 for 100 strips at Walmart. There are no strips called Insulinx here in Canada.
While these strips will work in the AT2 meter and are the same strips, the strips packaged under the AT2 brand have been batch tested to determine which cat code on the AT2 meter will give you the most lab equivalent result. There are 7 known cat codes on the AT2 meter. There may be more we are unaware of. The codes we know are 07, 08, 22, 37, 38, 92 and 93. So while folks have been reporting acceptable results with code 38 that is not necessarily going to consistently be the case.
While you will get a reading in the ballpark with the alternate strips, you stand roughly a 14% chance of getting the most accurate reading possible. I recently tried some Freestyle strips in my AT2 meter on code 7. One reading was within reasonable expectations while another was considerably higher than I would have expected. My previous tests with alternate strips using other codes often produced readings higher than those with the properly branded strips. This is where my concern lies in that a meter reading low will allow you to take necessary action in plenty of time should kitty be experiencing low BG but a meter reading high could delay action possibly leading to a symptomatic hypoglycemic event. Just my 2 cents.