Well Robert I can tell you this since I had to cut up many loquat fruits this weekend to harvest seeds I'm selling. I had approx. 300 each of the seeds from Vista White, KT4, and KT1-Kosmic fruits. And since I noticed this 1 Seed loquat fruits, I decided to see how many one seed fruits I would find in these 300 seeds harvest. Here's the numbers of 1 seed fruits found in these varieties which by the way are all growing next to each (6 large trees grouped in 20ftx20ft area).
1) Vista White - 11 fruits with 1 seed (out of 300 seeds total) - no I didn't count the total fruits
2) KT1-Kosmic - 2 fruits with 1 seed (out of 300 seeds total)
3) KT4-Teardrop- 3 fruits with 1 seed (out of 300 seeds total)
So to me this shows a rather small percentage of fruits would randomly have only 1 seed. This makes the probability of my 1 Seed loquat tree fruits even more higher that next year I may continue to have fruits with one seed, hopefully 90-100%
When I noticed the 1 seed on my seedling tree and started checking the fruits, I had 6 out of 6 fruits with 1 seed, wasn't checking the seed count of the fruits I ate before this.