This came up in this weeks game session,
Greater Magic Weapon +1 per four caster levels (maximum +5)
I have always taken this as; at 1st level you are +1, 5th +2, 9th +3 etc.
DM took it to mean caster level/4 round down. so levels 1-7 +1, 8-11 +2, 12-15 +3 etc.
Thoughts? Is there a ruling in the books that I missed?