The potro,
The Australian & US Opens are played on slightly different surfaces - One's Plexicushion and the other is bleu green cement....
This is an example from the patch i'm using
AUSTRALIAN OPEN
[Physics] // Plexicushion
Friction = 0.57 //0.58
Elasticity = 0.84 //0.61
MaxSkidAngleRatio= 0.30
SkidAngleRatioBase= 0.20
Sound = 4
SkidSound = 2
SurfaceSpeed = 0.65
Type = 4 // Hard
US OPEN
[Physics] // Bleu-green Cement
Friction = 0.58 //0.56 0.61
Elasticity = 0.81 //0.63 0.61
MaxSkidAngleRatio= 0.20
SkidAngleRatioBase= 0.20
Sound = 4
SkidSound = 2
SurfaceSpeed = 0.25
Type = 4 // Hard
As you can see and the same will be with an unmodded version they're slightly different surfaces

Reduce your 100% topspin!
Now a Question from me to you

Have you ever asked A question on this forum before without moaning about something?
