sounds like great results if you are getting smooth planing on maple. In order to take a fine finish pass , you'd need or use a finish planer or a wide belt sander even better.
The grainy spots in wood is always gonna give you some trouble, try tiger maple you'll see.
as far as sniping, many causes and usually it's on the way out not in.
read this, maybe the infeed roller is out of adjustment a slight amount
or the bed roller is high.
Thickness Planer Setup
the settings he describes and shows in the picture are spot on
This is more in depth of the same thing
http://wiki.vintagemachinery.org/Get...rformance.ashx