I think I said ‘more accepted’ and because Dylan says so 
and he has verified that his CFD sims on the Drivaer are within 1% of experimental… I think I have PM from him saying mostly 3 are good for him…
Because prism cells are better shaped to calculate the BL shear zone… I hope you mean ‘from’ and not ‘along’. The number along the surface is determined by level of surface refinement…
And I believe the reason for that is to make sure the air stays attached to the surface as laminar flow for as far back a possible on the low pressure surface, not because suction has more power than pressure, after all you can only ever have a maximum of about 15psi for suction while pressure side is virtually unlimited pressure…