I remember reading those articles, and then finding another website that said that there are accounts of it not being exactly correct. Keep in mind this was only a few people studies. I noticed with the pair that I picked up that one had more spangling, darker color, different body shape.. turned out, they were both females. I sold the other off..
I still really have no clue how to sex the Paratilapia other then getting them to spawn (which my females did many times) but the finnage and body shape might not always be exact..