Stacking benifits, not bonuses [3.P]

[gr8artist]

Ok, so we're running a laid-back Pathfinder campaign, but allowing 3.5 classes/feats/etc.
Party monk is wanting to deal more damage.
He's half-dragon (CR+2) in a party of level 7's, so he's got 5 levels in monk.
He has Monk's Robes for +5 levels in unarmed damage.
This simple brown robe, when worn, confers great ability in unarmed combat. If the wearer has levels in monk, her AC and unarmed damage is treated as a monk of five levels higher. If donned by a character with the Stunning Fist feat, the robe lets her make one additional stunning attack per day. If the character is not a monk, she gains the AC and unarmed damage of a 5th-level monk (although she does not add her Wisdom bonus to her AC). This AC bonus functions just like the monk's AC bonus.He is considering getting this:
Superior Unarmed Strike (boost monk damage +4 levels)
Your unarmed strikes have become increasingly deadly, enabling you to strike your foes in their most vulnerable areas.
Prerequisite
Improved Unarmed Strike (PH) , Base attack bonus +3,
Benefit
You deal more damage with your unarmed strikes... (table deleted to save space)
Special
If you are a monk, you instead deal unarmed damage as a monk four levels higher.
Now, do these two things stack? Will this level 5 monk be dealing the damage of a level 14 monk?

[Douglas]

This one is highly debatable, as demonstrated by various debates held on these boards about it in the past. It all depends on your answer to "higher than what?"

Some posters believe it means "higher than your actual Monk level". This would result in them not stacking.

Others, including me, believe that "higher than without this feat/item/whatever" is the more proper reading, which would result in full stacking.

For your own game, have your DM pick whichever makes more sense to him, or whichever he thinks will be better for party balance. RAW is ambiguous.

[Diarmuid]

Rather than SUS, why not just have him take Improved Natural Attack? Completely different effects which still nets the same result of larger damage dice with unarmed attacks.

[Siosilvar]

Given that the damage boost going from monk level 10 to 14 is 1.5 damage (going from 5.5 to 7), the question is "is 1.5 damage worth a feat?"

If your monk really wants to spend a feat for 1.5 damage, let him. It's not that great a use of a feat. Plus, he's a half-dragon, so it's not like he can get a size boost from Enlarge Person anyway, so he can't even use the better damage with a size increase to make it worth the slot without taking Improved Natural Attack, at which point he will have spent 2 feats for 5 damage... which still might not be worth it.