The "dive and drive" technique is more used with piston planes than it is with jets (correct me if im wrong).
The 737 FCTM asks you to add 50' to the MDA for NPA and VNAV/LNAV.
Speaking of the 737 when doing a GA the aircraft will decend at least 30-40' before it will initially climb away so hence the 50' add on to MDA.
During my JAA IR I was told to add 50' on top of the DA for an ILS which I never understood.