What do you mean by 16? Is that what you get in game? If so, maybe it's because you didn't loaded a clean module from your save game? (If the placeable has already been loaded, your changes will not appear if I remember correctly...I could be wrong on this though as it's been a while).
Btw, according to this:
http://nwn.bioware.com/developers/Bioware_Aurora_DoorPlaceableGFF.pdf) OpenLock DC corresponds to "DC to unlock this object, if this object has been locked
by setting Locked to 1."
In any event, my best advice is experiencing (that's how Holowan labs was able to develop)...try checking other doors & such in the game to see how the issue is being dealt with (if you find out, it'd be nice to post the details for future reference).