22psi tune map car hitting 18psi

I had my stage 2 map on Saturday. The first map was to request 22psi but the car would hit 18psi. 

It mapped to 256bhp but with the 22psi it should be around 280bhp. 

Dv changed

Pcv changed 

Can follower changed 

No evident leaks when we smoke tested it. 

Fuel trims were great 

They put another map on to request 19psi as the car is hitting 18psi  

The car is only 62k. They think it could be wastegate or the penny valve flap. 

Dont get me wrong the car feels great and pulls really well feels very quick but I would like to eventually find out why it wouldn't hit 22psi. 

Anyone got any ideas.