Crossbow DMG not same as in char sheet.

[Groburn]

So i made a crossbow build character and i do lower dmg than what is shown in character sheet.
My char has Master Crossbow Sniper feat with +6 DEX modifier which and +3 STR Modifier.
So dmg with +4 EB Crossbow looks like that:
1-10+4
+9piercing (Xbow Sniper Master)
+4Piercing (Enchant Bonus from Crossbow)

And my char never hit for more than 23-24dmg. Usually hits for 14-15 lowest.

My Crossbow doesn't have +Mighty on it so does STR modifier actually adds? It shows in character sheet that it adds but does it actually work without the +Mighty on item?
Does Enchantment Bonus on Crossbows add to +DMG or only adds +AB?

[Karond]

Crossbows without mighty does not add the STR modifier to damage.

Enchantment bonus on crossbows adds both AB and damage (like EB does on every weapon in the game).

Perhaps that +4 is just mentioned twice?

[Groburn]

Ohkay. Than that's the case. Because my Xbow doesn't have mighty but in character sheet it shows me that it adds the STR modifier to DMG. Guess the game mechanics just ignore that and don't actually add the STR modifier unless i have the +mighty.
Thanks Karond.