ICE Cache Problem ??

[eternal art]

I have a small crowds shot done via ICE particles and instance and everything works fine , then when i'm doing the cache for rendering the particles has changed and the number has increased about 3 times ?? it's weird .
Is there anyone got this strange behavior with ICE caching before ??

XSI 7.01 and 7.5 x64 - vista 64 .

any help ??