I don't see where 'both' ways comes into it- there is an Ops manual, and it is not being appreciated that the OP is adding increments of his own. Whilst under training, they want him to do it as is writ in OMB!
Let's not change the OPs question- it is quite clear what he is doing.
I would have had a tendency to 'bug' the UP speed + 5, giving a bit of leeway to the AFDS + A/T, especially in gusty conditions or with SID profiles that include fairly steep turns after departure. I have been told that I am incorrect to do so because I am 'breaking' the NADP profile?
It's quite easy- fly it as told by the trainers and OMB with no question of adding bits here and there 'for Mum'. When he has some experience, then take it up with the training department. In the meantime, learn to bend with various training opinions that sometimes may seem to contradict themselves- that comes from experienced trainers. But variations of procedures from a learner are not ideal!
Although i believe nothing in our SOPs suggest this, I was led to believe that a mximum of the UP speed + 10kts could be maintained until above 3000 AGL and acceleration is initiated.
AFAIK, this is not 'official' procedure. Given half a chance, I bang it up to 250kt as soon as poss, and if I can get away with it, 300kt. You might have some old woman bleating about that, but there is nothing wrong with it, especially when you have a schedule to keep up! (apologies to older females- it is not meant to offend!).