Salman Maqbool

Hello I am designing an rc gantry beam of 80 feet span crane loads. The problem I am facing is regarding the stiffness modifiers. According to aci we can use 0.5Ig modifier for beam when checking for deflection. Can I increase this modifier to 0.7Ig or 1Ig for checking service deflection. The allowable deflection for the gantry is L/2000 as notified by the supplier.