is there no point in getting higher level staff???

I'm trying to understand the game mechanics and have started to notice some things that don't make sense. I was hoping someone would ha e some answers:

1. I replaced a level 2 Commercial Manager with with one who is level 7 AND who has higher attributes. Yet I noticed that the revenue from commercial activity at subsequent races, is exactly the same. It appears there is no point in hiring better staff.
2. Is there any difference in hiring a better technical director, designer, doctor, etc.?
3. Unlike drivers, the rest of the staff do not appear to level up. Is that a bug or intentional? I don't understand why they wouldn't.
4. Is a car with 5A components better than a car with 4A components? I noticed that other teams with higher components 5 but let's say 40% performance, appear to be faster than a 4 car with 60%+ performance. Normal or could it just be down to driver differences?

Thanks for any answers that you may have,

Eyo Sama...

Hello Eyo, thank you for your questions. These issues have been discussed before on the forum but I'll make a quick summary for you this once.
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[*]Commercial Manager effects your revenue from your commercial market by it's level. This feature however is not active.
[*]The Technical Director supplies information on your race, currently however there is bad coding for the Technical Director which at level 20 will tell you run with far far less fuel per lap. The Designer does work and effects the speed of development, a high level Chief Designer will bring in new parts faster. The Doctor's level is to reduce the stat loss of drivers through atrophy, though this has not be confirmed, we believe it is very unlikely.
[*]All staff members do not level up at this time as their contributions as such as not be implimented. This game is a released but pretty much still in a development state. Many features are not working and the game was rushed for release. Many problems are rectified in Q2 but not Staff.
[*]All car versions are different depending on the % of the component. 5A is not always better than 4A, however there is an overhaul for the design system which eliminates the linear path the design system currently has.
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For now, Race hard, climb the Ladder, learn from the best.