If you have to stop the program or you get a power failure do not rely only on the home position you wrote down. Rather start the program and run the first part with water only and check that it follows the cut that you have already done. You may also want to move it to another portion of the program and check that it still lines up there too. I am always concerned that when restarting a program you could be a few to several thousands of an inch out of position and this might not be good.