My understanding is that while it's relatively simple to make a single AB-buff ninjutsu for athletics or Taijutsu, seducing chakraAI into going further than that becomes substantially harder.
We've seen plenty of double AB buffs, but very very few triple AB buffs. Similarly, to my knowledge Strength of the Storm is the only quadruple buff that we are aware of.
That suggests to me that it is much, much harder to create a technique that offers such large bonuses. Remember, we learned that chakraAI really wants to make basic fireballs and is far less interested in making the better stuff.
If it wasn't substantially harder to make higher multi-tags, wouldn't we see a bunch of ninja running around with quintuple or sextuple AB buffs? There's certainly plenty of interest in making those techniques and countless situations where it would be well worth the additional chakra cost.
@eaglejarl @Paperclipped @Velorien, does this match what Hazō was taught?