Physics behaviour changes when adding more layouts

Hi, here's my situation:

I created a layout added some objects to experiment with physics behaviour.

Object 1 (circular): a ball, default physics behaviour, collision mask = circle, bullet = yes

Object 2 & 3 (rectangular): two pieces of wooden plank, default physics behaviour, Immovable = YES, prevent rotation = YES (because they need to be static on the screen), collision mask = bounding box.

and nothing else fancy, no forloops or everytick conditions in the events..

Basically, the idea is to let the ball under gravity and bounce off the wooden planks.. when I preview just that layout in the browser, its awesome smooth and my FPS count shows 59-60 FPS on chrome & firefox (both with canvas2d and WebGL).

BUT when I add a second layout with a button (to act as a splash screen) so that when I click on that button, am taken to the first layout(where we have the physics going on), and when I start from the splash layout in both browsers preview, the trajectory of the ball changes slightly.. it appears to have lost speed and bounces off the planks differently. FPS count still 59-60 though. Its strange.

Has anyone come across this before? Please help if possible...

Thanks.

Could you post a capx for us to have a look at? I'm having some issues with physics in r154 but I can't be sure whether or not it's my computer's age that's causing my problems...