Tom,
I think that BizJetJock has highlighted an important issue. We, as commercial pilots, are bound by several parameters: firstly, what the AFM says that the aircraft is capable of, secondly what the Regulating Authority says is legal, and thirdly what the AOC of your particular company has decided to do (potentially more restrictive than the other two).
Rightly or wrongly, we are bound by the AOC, which is an evolving document and should, with time, address any anomalies that might occur. On the Hawker in my operation, the Authority, the AFM and the AOC allow either flap 0 or flap15 take-offs. The AFM publishes second segment climb profiles for both and under certain circumstances we get a better rate and gradient using flap 0. However, the AFM doesn't publish a profile for a combination of flap 0 and flap 15 to 1500', therefore we have to use one or the other.
The practical advantage of flying flap 15 to 1500' with both engines operating is that the aircraft is already configured such that it will give a known climb gradient if one engine fails at any point between V1 and 1500' agl provided that climb power is set on the operating engine and the aircraft is pitched to climb at V2. Of course, with two engines operating we will follow the SID which, unless stated otherwise, has a Terps climb gradient requirement of 300' per nm or so to clear obstacles (or 900'pm at 180 kts).
Therefore, all you need to do with a fully functioning aircraft is to climb at a sensible speed and adjust rate of climb with power such that you at least achieve the required SID climb gradient. If an engine fails before 1500', apply climb power and pitch for V2. However, if your AOC says that you must leave climb power set until 1500' regardless of how many engines are operating just in case one fails and you forget to apply climb power to the live one then you have another set of problems to contend with, particularly on a cold day out of Farnborough with an initial level-off at 2200 agl !
Of course, without an AOC, operators are only bound by the law and the AFM. It is often the ambiguous wording of AOCs that causes pilots to fly illogical procedures and these anomalies should be highlighted to the Operator for possible amendment.
AP