BBM video Z10 -> Q10 poor performance

Hi, i have a Q10 and just received a Z10 for christmas. I played a little bit with BBM video and here is the result.
I use my home wifi for the both mobiles.

1) i initiate from my Q10 a BBM video to my Z10
Smooth video, screen sharing (from my Q10) is also smooth. Overall a good experience.

2) i initiate from my Z10 a BBM video to my Q10
Bad video performance, delays with screen sharing (from my Z10). Bad experience.

Both mobiles have a latest official SW version.

an idea ?
Thanks,

How many times did you perform this experiment?

3 times ...

Weird. When I start a video call to Q10 users with my Z10, everything seems fine.

Are the qualities of both parties poor? Or just one side?

for me just for one side ... : call Q10 user with my Z10 is ... not the same than the inverse.