Zen archer Ki Arrows

[Atalius]

Ki Arrows (Su)
At 5th level, a zen archer may spend 1 point from his ki pool as a swift action to change the damage dice of arrows he shoots to that of his unarmed strikes. This lasts until the start of his next turn. For example, a Medium zen archer’s short bow normally deals 1d6 damage; using this ability, his arrows deal 1d8 damage until the start of his next turn.

My question is if he's 5th level his unarmed strike damage indicates 1D8 so would it go to 2D6?

[Syries]

You use the unarmed strike table at the listed level. At level 5 the monks unarmed strike is 1d8, or 1d6 if you're small sized. Coincidentally that's the damage dice of an appropriately sized longbow so that ability is basically useless for you until you get higher unarmed strike damage dice, at later levels.

[Atalius]

Oh cool, so it would be quite significant at higher levels

[Syries]

Keep in mind that spending ki for an extra attack is also a swift action. getting 5 attacks at 1d8+mods tends to be better than 4 attacks at 1d10 or even 2d6+mods.