quoted by Nagamaki on theorderls.com, someone who did extensive testing with subtle blow
http://www.theorderls.com/phpBB2/viewtopic.php?t=3761 :
"OK after all my tests here's what I can state as fact :
TP gain and TP given
When you hit a mob, you and the mob will gain a base amount of TP based on your current attack delay (AD). This AD includes Job Trait speed modifiers like Martial Arts and Dual Speed, but not Haste/Slow gear or spells/songs. The TP you gain is proportionnal to AD, faster = less per hit but same amount of TP as a slower weapon over time assuming both always hit and no other modifiers come into play.
This is why a Lv75 MNK gets less TP gain per hit than a Lv1 MNK with the same weapons.
Whatever the amount of TP you gain per hit, the mob will gain the same amount + 3.
Dagger gives you 5%, mob gets 8%. Naked WHM punching gives you 12%, mob gets 15%. Sword hit gives you say 7.2%, mob gets 10.2%. Spells that deal damage directly when cast (Dia, Bio, all nukes, Drain.. But not Choke/Burn/..) give 10%.
WS TP gain is actually quite simple. On your side, TP is based on hits. You get full TP from the first hit (or first 2 hits with HTH or Dual Wield) and 1% TP per extra hit. The mob gets the same amount of TP it would get from a normal melee round regardless of hits. So if you use a staff that gives the mob 13% normally, all staff WS will give 13%. If you use HTH (without subtle blow) that does 2 hits that each give 8% (5+3), all HTH WS will give 16% base. 1 hit or 8 hits, it doesn't matter.
Subtle Blow
Subtle Blow works the same way Store TP does, except its a % of reduction applied to mob's TP instead of an increase to yours. A HTH hit that gives you 5% TP gives the mob a base amount of 8%. With +25 Subtle Blow, the mob will gain 75% of the amount, so 6%. A staff hit that would give 13% will give 9.75%, and so on.
Based on my calculations, MNK75 gets 25 Subtle Blow from Job Traits gained over levels. I don't know the exact spread of upgrades, but MNK gets Subtle Blow at lv5 for the 1st time. I'm *guessing* NIN75 gets 20 Subtle Blow, since their first Subtle Blow is at Lv15 (I tested lv5 and lv15 by subbing them on lv19 and 30 jobs). A NIN75 with BST sub could easily test this, my NIN is only 55 so I can't get the end game numbers myself.
Subtle Blow applies to ALL ways in which you directly give the mob TP, melee WS or spells. Pet actions are not affected (avatar melee, anything BST pets do, wyverns)."