I have told the Topaz that it has 73 nozzles installed, and selected to use 73 nozzles for the LED's. THe 74 nozzles are actually on the machine.
I think it has something to do with the part dimensions in the vision section. The part is 5mm x 6mm x 3mm. With a search area of 5mm, that tells the vision system that any reflective spots in a 15mm x 16mm rectangle are for this part. So, the vision may tell it not to load any parts next to the LED's, since when rotating, they may hit one another, or get in one anothers vision area.