This is a cut of a draft of AC 120-OBS-11. Looks like the fed's are trying to clear up this matter. I don't know if this has been relased as an AC. I highlighted some of the pertinent language.
TERPS CRITERIA VS. ENGINE-OUT REQUIREMENTS:
Standard Instrument Departures (SIDS) or departure procedures (DPs) based on U.S. Standards for Terminal Instrument Procedures (TERPS) or ICAO Pans-Ops are based on normal (all-engine) operations. Thus, engine-out obstacle clearance requirements and the all-engine TERPS requirements are independent. Engine-out procedures do not need to meet TERPS requirements. Further, compliance with TERPS climb gradient requirements do not necessarily assure that engine-out obstacle clearance requirements are met. Terminal instrument procedures typically use specified all-engine climb gradients to an altitude, rather than certified engine-out airplane performance. Terminal instrument procedures typically assume a climb gradient of 200 feet per nautical mile (nm) unless a greater gradient is specified. For the purposes of analyzing performance on procedures developed under TERPS or Pans-Ops, it is understood that any gradient requirement, specified or unspecified, will be treated as a plane which must not be penetrated from above until reaching the stated height, rather than as a gradient which must be exceeded at all points in the path. Operators must comply with FAR requirements for the development of takeoff performance data and procedures. There are differences between TERPS and engine-out criteria, including the lateral and vertical obstacle clearance requirements. An engine failure during takeoff is a non-normal condition, and therefore, takes precedence over noise abatement, air traffic, SID’s, DPs, and other normal operating considerations.