Diva analysis grid + unexpected results

hello all,

i am trying to get daylight autonomy results using diva for gh. 

two questions regarding this:

1. it looks like im getting the same grid from the Analysis Grid component no matter what input I have in the Grid Size parameter - am i using it the right way? (script attached)

2. im getting different results when using Diva4Rhino and Diva4Grasshopper for the exact same geometry and conditions. what may cause this? it looks like the Diva4Rhino results are more likely to be correct (images attached)

your help's appreciated..

thanks

noam