Are there any tricks to planing the top of a box flush?
In this case I made a dovetailed box, and glued it up with bottom and top attached. The idea being to saw off the top and thus create the lid.

Unfortunately, there was a little rocking during four runs through the table saw and now I have some rough edges to flush on top and bottom. I've run into this issue of flush planing four adjacent edges before on picture frames and always get stuck with sloped edges, tearout when going from longrain to cross-grain, etc...

Is there a correct way to do this?

Box pic prior to cutting, for referencecherrybox.jpg