Ok that makes sense. I feel my rubbers wear out a lot quicker, do 40+ balls weigh more than celluloid balls baal?
Yes. Most celluloid balls were 2.66 g or so and pretty much all were less than 2.70 -- certainly any of the ones ever used in tournaments. A lot of 40+ balls are 2.73 to 2.76. The DHS 40+ balls that first came out (the ones made of celluose acetate) were 2.78!
The lightest 40+ ball is the Nittaku Premium at ~2.68 - 2.69 followed by the new D40+ at ~2.73. It may not seem like much more than celluloid but it makes a difference. Plastic balls also have slightly larger diameter. ABS balls are also harder and presumably deform less on contact. In fact, the increases weight and diameter is why the new balls are called 40+. I think it could increase the wear rate of rubber (also the surface texture and hardness of the new ball).
By the way, ITTF simply says they are enforcing rules on ball weight that were always in place but which they had been lax in enforcing since pretty much forever. They slipped in the increase in size the same time that they mandated the change in material that they attributed to the "impending world-wide shortage of celluloid" which of course, does not exist. The increase in size was because of..... what? To slow the game down more? To reduce the spin? To make the ball easier to see? To try to beat the Chinese? Who knows. They have never given a reason as to why they suddenly found religion on that particular rule that they had never had before.
I think a great deal of what people find different about playing with plastic balls can be attributed to their larger size. Of course, the cellulose acetate garbage is almost never round and bounces low and breaks all the time and is expensive and thankfully we will hopefully be rid of those.