CV,
Hopefully in a few weeks you will be a TATC
- a small point but you might as well start right.
And your right, there isn't a huge amount of maths involved in training or on the job, but as you say the ability to convert speed to time is very handy.
As for the test, I guess NATS have to whittle down the application pool somehow and this is just one in a long list of ways they have of doing so.