I'm not sure where exactly I got the notion of playing finger per semi-tone, but none the less I adopted this technique early on in my studies. It is a technique that just made sense to me and felt right. Flash forward to me purchasing and subsequently studying on my first unlined fretless and I finally feel justified having practiced and internalized this technique. Finger per semi-tone has saved my life when learning to play unlined fretless I have to tell you. Low on the neck its not that tricky to find the semi-tone between the dots. Though once you get past the 9th position dot you now have two semi tones between dots. This all might sound like elementary stuff to you guys but I'm just now learning this stuff. Keeping to a finger per semi-tone has saved me so much time and effort. I'm not going to say its "easy" but Its taken a LOT of work out of getting my intonation down. Making jumps is still tricky but its getting better. When I consider that the origin of finger per semi-tone technique is probably from classical string players it becomes clear why this is an advantageous way to learn the fingerboard.