Except on their own the definitions ARE unclear. But the definitions are still useful ... if given sufficient explanation and put in the right context.
"Which decision altitude? For aircraft emergency bailout or what? No, we're talking about your malfunction decision altitude."
"What hard deck? For last CRW dock? For last novice freefall maneuver initiation? For dealing with a malfunction (i.e., same as the malfunction decision altitude, as long as one isn't already below it)? No, we're talking about your cutaway hard deck. "
And if you have a 2000' decision altitude, you don't HAVE to ride a mal down to the 2000' decision altitude. And if you are at 1800', you can still make that decision to cutaway.