"...prior to level acceleration."

[Gominder]

I fly on B737 and our company procedure is to ignore these "climb to .... ft prior level acceleration". The reason is stated, because all missed appr. and departures are calculated with fixed min. climb gradients (something around 2,5%). As long as you can safisty that, you can accelerate and climb at once.
For airplanes like heavy x-weight B747´s etc. they have to watch that and to remain on v2+... until passing the constrained altitude.
You will find details of construction of dep.+missed app. in ths Jeppy and the aip´s of the country.
Needless to say, that in case of engine failure the obstacle clearence is most important. Is there are a special engine failure procedure for that ATH dep. runway?