Good evening.
Bestglidespeed, you might be interested in this thread.
http://www.pprune.org/forums/showthread.php?t=316884
Because most all-engines climb data provided to line pilots is not continuous from take-off through flap retraction, most of the time you cannot predict your actual compliance with a SID gradient.
This is a known problem. All engine climb profiles are not always steeper than the engine out versions, there is no certification requirement to produce all engine profiles (although manufacturers may produce some useful data as part of a community noise document for the FAA), and the forensic method of measuring actual climb performance takes place after you've already made the contract with ATC that you'd actually do it. Hard to explain when your aircraft is grossly underclimbing and can't safely make up the difference.
This won't change till the regulators force the data to be produced.
IMHO
Vs