I don't know what "FNG" means (I'm 80 years old and lots of stuff go right over my head.
), but you are not the only one who simply "sticks" cuttings in soil media of some sort and have those cuttings root. I was taught by a Hawaiian grower, 30+ years ago, to callus my cuttings for 7-14 days (depends on the time of year) before rooting them. I still do this. I have rooted 1000's of cuttings, and do so 12 months each and every year. As you have noted, rooting mid-stem cuttings is more difficult to do. That's simply because those cuttings are trying to root and at the same time, trying to branch. Cuttings only have so much "energy" to do these two things.