Statement
look at paragragh 5.3.3 AIP ENR
It states that you must add 50ft if using forcast Area QNH, it doesn't state the Jepp part about adding to the forcast terminal QNH minina.
So I think that you need to add it, purely because AIP would overrule the Jepps. Well I think so???
In saying this I feel that the approach has been designed not to add it but the above states that you must!