Improved Climb
This is a question for Old Smokey.... :> :> :>
I didn't read your quesiton carefully enough. You mentioned the 737. I assume OCTOPUS is for Airbus only, as my first experience with OCTOPUS is with an Asian carrier that operates the Bus.
I can quote you the FCOM with regard to this question, but I don't think that will answer your question.
IAS/TAS relationship has nothing to do with ground speed. During takeoff, the wings don't care how fast the wheels are turning. They're interested only in the airflow over them.
Boeing's improved climb philosophy considers a longer than needed runway...using up more runway than you'd normally need...to 'get a jump' on second-segment climb. It's normally used to the biggest advantage at high density altitude situations where you have a bunch of runway.
So, normally, you might consider a lesser flap setting for takeoff (although not necessarily), a longer takeoff roll, with a higher V1/Vr. This will give the aircraft 'a boost' if you lose one after V1.
In essence, you have much more runway than you need to get it stopped...but, you're getting tight on second-segment climb. So, you make a trade. Use more of that excessive runway, help yourself out on second-segment climb.
However, I'm always opposed to 'fudging' figures in the charts. Yes, Airbus says you can take the numbers for a five or ten knot tailwind, even though you may have a ten knot headwind. As long as you have the performance needed with the tailwind, it's really okay to actually have a headwind (more conservative). (Sort of like having numbers for a displaced-threshold departure...and then taking off using the whole runway.)
The crux of the issue is: how much runway do you want to sacrifice for second-segment climb? On some of the 737s, a FLAPS 1 takeoff is allowed. Doing so would use up more runway, but increase your second-segment climb gradient. Or, you could do a FLAPS 5...using an improved climb strategy, and come close to accomplishing the same thing.
It's interesting looking at OCTOPUS for the 320 series Airbus. Many times a FLAPS 2 gives a higher V1/Vr than FLAPS 1. Using FLAPS 2 would be an 'improved climb' situation. But, perhaps chosing FLAPS 1 would give lower speeds with a similar second-segment climb profile.
Again, I can quote you the FCOM with regard to all of this...what Airbus says. But, I don't think all of that is relevant to your question.
Tom