vtrix, I believe Colludium is correct.
I dragged the group out of the On Start of Layout section and got the incorrect spacing as you described.
So, I disabled the line "Sprite : Destroy", and then the sprites were spaced correctly.
Then I changed the Create object line to just create the Sprite on layer 0 at (0,0)
and on the next line Sprite : Set position to ( 300+ loopindex("y") * (sprite.Width+1), 300 + loopindex("x") * (sprite.Height+10) )
and that worked fine (even with the "Sprite : Destory" line re-activated). So, basically, it needs to already have a Sprite instance available to get its width and height. You just have to divide the line to create the Sprite first, then position it second rather than do it all on one line...