I recently bought a new 7 1/4" circular saw (Makita 5700NK) as my current one (about 10 yr old or more Skill model) doesn't have a micro adjustment screw to set the 0deg stop on the bevel angle (has a tab that you have to bend to get it to stop at 90deg) so it is hard to set it to correctly be at 90deg (base-plate to blade). The new Makita saw came with the base plate square to the blade (measured with a Kinex DIN 875/1 square) and the base-plate seems to be straight as far as I can tell. However, when I cut pine plywood with it, it didn't cut a 90deg angle. I though that perhaps the plywood was curved on edges and that is why this happened. However I also cut a new MDF (which is very straight and defect free) panel and it didn't make a straight 90deg angle either. The blade used is of reasonable quality (DeWalt 60 teeth fine cross cut). I had to adjust the micro-adjustment screw quite a bit to compensate for this and was finally able to set it such that it is cutting MDF with a 90deg/square angle. I checked the angle of the cut on the MDF with the same Kinex square and it is good. However, when I check the circ saw again with the Kinex square I find that now (as expected) the base plate of the saw is clearly not square to the blade. This makes me think that there might be a problem with the saw (like the depth of cut mechanism or whatever). Am I missing something here or is this because each blade will produce a slightly different angle when it is rotating at high speed vs when saw is stopped.

Should I return the saw (still within the 30 day return window) or keep it. I leaning towards returning it. And I am considering trying to figure out a way to square my current skill saw that is easier (using pieces of wood I make as stoppers to simulate effect of micro adjustment screw) or something else.

I am totally open to suggestions here!