Adjust iTunes volume through Applescript

decreaseITunesVolume.scpt

tell application "iTunes"
		set vol to sound volume
		set vol to vol - 10
		if vol is less than 0 then
			set vol to 0
		end if
		set the sound volume to vol
end tell

increaseITunesVolume.scpt

tell application "iTunes"
		set vol to sound volume
		set vol to vol + 10
		if vol is greater than 100 then
			set vol to 100
		end if
		set the sound volume to vol
end tell