I've just ran this on some of my games and the results are amazing!

Crazy Taxi: Fare Wars. ISO = 885,088KB CSO = 339,814KB (545MB Saved!)
Transformers The Game. ISO = 797,504KB CSO = 518,291KB
LocoRoco. ISO = 575,936 CSO = 517,231KB

Fantastic tip Harrison. Thanks!