When Donald Self draws the picture of the safe manufacturer's logo, the circles are not complete and look more like the digit '6'. In a next shot, there are three perfect circles on the notepad.
When Don Self is in Griffin Oren's office and Oren opens his safe, the bars on Roland Glenn's computer skyrocket, but when he closes it the bars dive back down to nothing. The device would have still picked up some chatter from Oren's computers, phones, etc, not as much, but still. The bars wouldn't have just plummeted to nothing.