I am surprised about how little your installer knew!
Makes one question his competency overall. Should his work be double checked?
I struggle trusting "experts" or "professionals". This is a prime example of why I have this mistrust.
Anyway, here is the manual for your stove, read it completely and use it to make sure your install is safe.
https://jotul.com/us/products/wood-stoves/_attachment/47427?_download=true&_ts=159652675b5
There is a break in procedure on page 15. If any trouble arises from not following it I think that it would probably be gasket or gasket cement failure.
Place your thermometer centered on the stove top, this information is also in the manual.
Good luck! Enjoy your stove but it is time for a crash course and to NOT listen to your local "experts".
I would be tempted to contact Jotul up in Maine and inform them how poorly their local sales team knows their product! How they provided you with misleading information too.
See what effects they feel not breaking in the stove as per the manual will have long term.
Dave