All right, but it is not what i'm asking. I try in simpler way.
1)now
-you bought xbow - you can shoot
-you bought xbow+pack of bolts - you can shoot
-you have pack of 13 bolts - you can shoot 14 times
2)should be
-you bought xbow - you can't shoot
-you bought xbow+pack of bolts - you can shoot
-you have pack of 13 bolts - you can shoot 13 times
I hope now is clear what I'm asking about. I know that sometimes my questions about game mechanics are "philosophical" but the devil is in the details