Also looks like a good application for dual tolerance, one to control shape at a tight tolerance relative to A or A|B, and a looser tolerance for location A|B|C.
It's not drag so much as each blade's wake causing interference with the next. There's are tradeoffs between speed, number of blades, and weight.
The ultimate boogeyman is the Betz limit. There is a theoretical maximum amount of energy that can be extracted from a given cross-section of wind...
If you're making this determination based on the requirements of the design fit and function requirements, fine.
If you're making this determination because that 0.05mm "doesn't seem like a lot", you need to step away.
[bat]Honesty may be the best policy, but insanity is a better defense.[bat]...
Basic dimensions are exact, ideal dimensions. They have no tolerance, therefore no tolerance or precision is implied by decimal places. Trailing zeroes are implied and infinite.
The problem is that someone somewhere decided your default should use three default planes instead of a single absolute CSYS.
Incompetent people are everywhere. Some make CAD templates.
Consider going the opposite direction: Use holes as datum and control slot and profile.
Final GD&T does not necessarily need to follow order of operations for manufacturing (which may or may not correspond with actual part function).
EVERY German drawing? I've been to Germany. It is a big place. Many people. Many companies, some of which are undoubtedly creating engineering drawings.
Keeping your $#!+ together when it is not together is a powerfully daunting task.
Like most things in life, it happens one little thing at a time. How does a piranha eat a pig? One bite at a time. Be a piranha, not a shark. Bonus if you can find some piranha buddies to help you.
As CWB1 said, be direct. Be clear.
Most of all, ANSWER THE QUESTION. As an interviewer, one of the biggest red flags is if the candidate does not understand the question or (worse) understands but gives a deflecting answer.
Anyone might ramble when they are nervous. I try to give some leeway...
