An oscillating tool can be a useful gadget for making precision cuts. I needed to place a flooring plank next to an existing door jam. The normal practice would be to measure and cut the plank to fit around the jam. However, it is possible to take the opposite approach and cut the door jam to accommodate the plank.
It was a simple matter to use the existing plank as a guide to mark the height of the cut and then use an oscillating tool to make the cut. See the photos below.