Rick
You raise some interesting points regarding the base level for a chute pull.
A climbing aircraft maybe climbing at 700fpm and abruptly loosing an engine would still have some upward momentum when the chute is pulled.
I would imagine this would have an effect on the chute being successful at a lower than base level as there would be less deceleration for the chute to counteract over a pull with an aircraft descending at maybe 700 fpm?
Probably further research could establish better guidelines.
Maybe now we can get to some sensible discussion
Pace