to what level should the drawn design match the real web site

Question

I am working on a web site. The client has drawn it in Microsoft Publisher, and I am using this drawing as a working graphical design. The problem is that there are a lot of places on the web site where a text block's margin differs in few pixels, or an image is few pixels far from where it is in the drawing. I wonder if the drawn design really should match the web site pixel-to-pixel, or is it a common practice to have some things differ in few pixels? I wouldn't really want to spend any time correcting those small errors. This is boring and looks like a time waste.