Here is a summary of some of the points in the study.
Surface temperature is key. Bounce can as much as double, or be cut in half, depending on the surface temperature of the ball.
Faster balls are only sometimes faster. So called "faster" and "livelier" balls may bounce less, the same, or more than a "hot Pro", depending on their surface temperature.
Hang time was less. Dunlop advertises 10%, 20%, and 40% increases in "hang time" for its line of balls. Rebound tests showed increases of 1%, 7%, and 14%.
Bounce decreased with skill level. For the players measured in the study, the was a general trend was: the lower the skill level, the lower the bounce.
Lower skilled players played a more difficult version of the game. The lower the bounce, the harder it is to rally. Bounce decreased with skill level. Those players experienced the low bounce penalty.
Surface Temperature can be a guide in ball selection. Players can avoid the low bounce penalty, and approximate the bounce of a "hot Pro", by selecting the appropriate ball. Surface temperature can be used a guide in ball selection.
One ball does not fit all. Squash balls are so temperature sensitive that a specific model of ball will only bounce well for a range of players. Unlike other ball sports, squash requires a line of balls which bounce well at different surface temperatures.