Atack, spells and runes

[ayla]

local combat = createCombatObject()
setCombatParam(combat, COMBAT_PARAM_TARGETCASTERORTOPMOST, true)
setCombatParam(combat, COMBAT_PARAM_TYPE, COMBAT_DEATHDAMAGE)
setCombatParam(combat, COMBAT_PARAM_EFFECT, CONST_ME_MORTAREA)
setCombatParam(combat, COMBAT_PARAM_DISTANCEEFFECT, CONST_ANI_SUDDENDEATH)
setCombatFormula(combat, COMBAT_FORMULA_LEVELMAGIC, -1, -60, -1, -60, 5, 5, 4, 7)

function onCastSpell(cid, var)
return doCombat(cid, combat, var)
end

what i should edit if i want to reduce, his atack at 50%
could some explain me? ?
pleaseeeeeeeeeeee.

 

[Cykotitan]

local combat = createCombatObject()
setCombatParam(combat, COMBAT_PARAM_TARGETCASTERORTOPMOST, true)
setCombatParam(combat, COMBAT_PARAM_TYPE, COMBAT_DEATHDAMAGE)
setCombatParam(combat, COMBAT_PARAM_EFFECT, CONST_ME_MORTAREA)
setCombatParam(combat, COMBAT_PARAM_DISTANCEEFFECT, CONST_ANI_SUDDENDEATH)
setCombatFormula(combat, COMBAT_FORMULA_LEVELMAGIC, -1, -60, -1, -60, 7, 7, 3, 5.25)

function onCastSpell(cid, var)
	return doCombat(cid, combat, var)
end