In the jepps terminal section 4.10.2 it states "in executing a missed approach, pilots must follow the missed approach procedure specified for the instrument approach flown". To me that clearly states once you have commenced a missed approach, if it says track 123 and climb 3000, you track 123 and climb 3000. If you commence the missed approach before the missed approach point, fine, you will have some altitude in your back pocket... but you must still track to the missed approach point and "follow the missed approach procedure specified for the instrument approach flown".