ShiKage's Ultimate Hayato Guide

I have two questions.
1. For bossing which is better Sanrenzan or Jinsoku?
2. Why use Falcon dive over Whirlwind cut?
Falcon dive 1 and max:
[table=]MP Cost: 25, Max Enemies Hit: 8, Damage: 152%, Number of Attacks: 6, Stun Chance: 24%, Stun Duration: 6 sec, Stunned Enemy Damage Taken: +110%. \nPassive Effect: Shouryuusen, Dankuusen, and Whirlwind Cut Damage +62%
MP Cost: 45, Max Enemies Hit: 8, Damage: 190%, Number of Attacks: 6, Stun Chance: 100%, Stun Duration: 10 sec, Stunned Enemy Damage Taken: +110%. \nPassive Effect: Shouryuusen, Dankuusen, and Whirlwind Cut Damage +100%[/table]
Whirlwind cut maxed:
[table=]Active Effect: MP Cost: 33, Max Enemies Hit: 6, Damage: 380%, Number of Attacks: 3, Critical When Combined with Shouryuusen: 100%\nPassive Effect: Shouryuusen, Dankuusen Damage: +50% [/table]

Level 1 FD damage: 152*6 = 912%
Maxed FD damage: 190*6 = 1140%

Whirlwind (with lvl 1FD) = (380+62)*3 = 1326%
Whirlwind (max FD) = (380+100)*3 = 1440%

Is there something I'm missing or is it used because its movement is different and it hits 2 more mobs?

Link will be able to confirm, but I believe it has to do with iframes and mobility.