I have never heard of the enneagram system, but I suspect I may be a fellow 5. It is very difficult to say no to your manager, with my current one we have a good relationship and I can feel free to say no, sorry, can't right now, or okay then which of the other million priorities am I putting off for this? And I can be sarcastic about it too and we will laugh and most of the time I will probably still do all or part of the request anyway. Although sometimes I suggest an alternate method of getting her request completed and she goes for it. Damn I am gonna miss her when she retires. Anyway, my personal bet is that since you've shown yourself to be an effective employee and good at learning new things in the past, there's a good chance they will see it as a reasonable request.