I had this problem with my Bon Voyage after I got too good at it and rolled it over 5 times and still had lots of balls to play. I was able to get it dialed back by changing the setting to give a free play rather than an extra ball. This applies to getting either the special or the set high score. Not sure if C37 has a similar setting.
Beyond that, the other idea I had is that you could set up a fairly simple single-digit LED display, maybe run by a Arduino, that could be used to track 100k rollovers. It would have to be mounted somewhere somewhat unobtrusive, it wouldn't go very well with an EM backglass. It could be manually incremented and reset with some buttons, or if you wanted to get fancy it could be tied into the 10,000 score reel switch and the reset switch to run it automatically. Might be a fun project to goof around with.