I have not had anywhere near that number of misvends with these machines. As long as you have them shimmed correctly, they should vend just fine.
Attached is a photo of the sensor, follow the sensor cable up to the main control board. You will want to cut the outer conductors (in the picture it would be the Black and the Blue) and short (connect) them together back towards the main control board.....leaving them unconnected back towards the sensor. This would basically tell the control board that it is ALWAYS seeing the sensor.
Now as mentioned in previous posts, this will prevent you from sensing a mis-vend, or a product left in the delivery chute, however I have done this with 2 5591's for over two years and have NEVER had to bottles hit and break, or see an increase in misvends and angry customers.
I will also say, do this at your own risk and be careful. Also, remove power from the machine BEFORE doing this work. If you do decide to do this, ensure that you test afterwards to ensure full operation (other than the drop sensor).
Travis