Les, it's good to read that you've mastered the tool, it is with any cheap, if not poorly designed tool it will work, it's in how to best make work, should it be the only tool you have to hand.
The roughing cuts are not just at 90° to the work, but as you've found before, if not with this tool is a planing cut, tool rolled an angled pointing in the direction of the cut bevel contact, a skew cut as you have mentioned, given the larger cutting wing of this tool.
IMHO .. This form of tool could still be a problem to the uninitiated .. Just as the skew still to some, but I start to digress from the thread.
Cheers Dewi