I have a Cape with a chimney in the front center roof. It is leaking into the living room below. It has a lan, or apron, style flashing, where the chimney is built up to the roof line, a large piece of lead is laid over the entire chimney, holes are cut for the flues, and the bricks are then laid on top of it to final height. 

i have had five masons give me estimates. The bricks are in great shape. Two want to take the chimney down to the roofline and replace the pan (apron?) flashing and rebuild it. They say it will leak if they install new step flashing. Three masons say the other guys just want to get paid for more work, and they can cut in new step flashing. 

I want to ensure no leaks, without being taken for a ride.