The Latin RX7

Hello everybody I have a 91 turbo fc running a microtech and when I put timing lock to time the engine with a timing gun I lined up the leading mark to the timing cover, and the CAS is almost if not at the middle position, however my mechanic said thats way too advanced and i could blow up the engine... can this be true? i went over to check the timing again and the 5atdc mark is exactly lined up with the timing cover pin... is my mechanic right or am I doing it the right way? He says the CAS should be almost all the way retarded (rotating it counterclockwise)....
The photo is how my cas is positioned right now

NCross

iTrader: (18)

The CAS is usually about 70% to the right once timed to the yellow mark.