Audits do reset on some forms of update - like full installations for corrupted SD cards for example. Its never a tried and true measure of 'usage' so I always try to over-communicate the state of a game through lots of pictures and closeups of the playfield. Make sure to capture photos around various posts and high wear areas like shooter lane and scoops.

As for pricing a quick search here is useful to see what past games have gone for: https://pinside.com/pinball/market/classifieds/archive?s=1&radius_latitude=44.900041387317&radius_longitude=-93.655639648438&keywords=batman+66&ad_condition=0&machine_type=&ad_machine_manuf=&year_from=&year_to=&radius_distancekm=0&sort_by=ad_end_date&sort_order=DESC#results

I'd guess right now you are looking at between 7500-8000 give or take. Right now though is a particularly bad time to list a pin though unless its a rare bird or incredibly priced. You have the convergence of Spooky's imminent announcement and Mandalorian becoming available and hence requiring payment in full from people. I always find it best to list about a month+ after these types of events once the hype has died down and people are back to looking for what they want not what the masses dictate