I really don't understand your insistence on using 4 APs. As Doug said above, that creates a huge problem and it makes you chase issues that are simply best avoided. In the world of WiFi a congregation of APs is the cause of countless problems, diminished throughput and the genesis of threads like this one.
I had the great pleasure of having to manage the setup that Doug described above for several months and I will tell you that anytime we had a second AP fire up, it was hell. Even when testing and performing maintenance of the equipment, I had to make sure to never have more than one AP fired up at a time, unless I wanted to waste a few hours chasing ghosts. I have had hubs lock up on me and refuse to talk to the AP simply because it had seen another one. I have had to coax them back to life, with a hammer, harsh language and a screwdriver.
The next time you set up, just have a single AP fired up. Then when the targets appear on it, make sure you input the dimensions and offsets for each of the targets and then run your match. When you're done, take a backup and then if you want, you can upload the backup to the other APs and they will all have the same information.