I wonder if this is the reality, and if so, why people throw millions on lvl.6 and lvl.7 coaches (or even lvl.5 ones), when a slightly worse one costs alnist nothing, as according to current prices, my assumption states that the difference should be at least 10% per level, starting from lvl. 5
The problem is not with the training speed but with the players (I mean us, the gamers) mindset. Imagine everyone knew and can calculate correctly the financial gain from having a better coach. Then the prices of the high-level coaches wouldn't be so inflated, but still will be significantly higher.
Because I had to buy a coach quickly for my first training session (just started the game 3 days ago), I made a quick research on the Staff market for level 4 and level 5 coaches (more about level 4). Depending on the purchasing price and the salary of the players I made calculation how much you would pay for a lvl 4 coach on a 24-weeks contract and how much you would pay for a lvl 5 coaches.
For the lvl 4 the prices varied between 395k and 550k roughly, with most coaches in the 400-450 interval. If you are really patient you may buy someone for as low as 350-360k. Some coaches with specialties might cost more than 500k.
For the lvl 5 I have less of statistical data but again for 24 weeks you would pay for a lvl 5 coach between 1.2m and 1.4m. Obviously much more than the assumed 3% difference in effectiveness.
And only one example for a lvl 6 coach - price for 24 weeks would be around 2.9m
The price raise is exponential while the effectiveness is linear. That's true probably because some players want the best no matter the price. 3% more is still 3% more
And players training National players will also want the best coach. Also money is not issue for some hard training teams I guess.