Sweet Surrender
For an ILS the minima is annotated
D A(H), whereas for an NPA the minima is annotated
MD A(H).
From Jeppesen Introduction, Chart Glossary, come the following definitions. I've used the ICAO definition rather than the US one.
Decision Altitude/Height
A specified altitude or height (A/H) in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established.
Minimum Descent Altitude/Height MD A(H)
A specified altitude or height in a non precision approach or circling approach below which descent may not be made without visual reference
The germaine differences between the two definitions is that for a precision approach, one initiates a missed approach if not visual at the DA(H), whereas with an NPA, one may not descent below the MDA unless visual.
If the missed approach is not initiated until reaching the DA(H) then inertia will carry the aircraft below the D A(H) and this is taken into account when the procedure is designed. Reality is that (in poor weather) the decision is not made until the DH, then the appropriate attitude and power changes are made, with human lag, so, the DA can't be a not-below limit.