I'm not gonna get involved in the why, but in short it's a lottery and if you're not that 1 in 20 who has the right anatomy then it is NEVER gonna work for you no matter what adjustments are made. Most people on here never got it to work and either never came back on here or have been here for months or years ever since. The failures dwarf the successes but you won't hear about that much and on here people just disappear from their account when that reality dawn's on them.
Anyone who used to answer a lot of questions on those method have now stopped entirely because all the good advice in the world won't change the good or bad luck you'll have.