I would think if its same guy that breaks, and in same place. Not a coincidence , either same player being lil too rough, which is very likely with immature teenagers, or take a good look at the bumper on that side. If no apparent damage, I'd swap bumper to opposite side and/or consider adding 1/8"-1/4" washer to rod between man n bumper. yrs ago we played in high school over lunch hour, we were very rough on that DYNAMO -Twister coin-op table, never in 4 yrs while I was there did we ever break a man, lost 1/2 dozen balls. so we made mold in shop class, started making balls from diff resins, roughing them up with diff processes. hope you've solved mystery , I curious to find out if you did?