Additional director in pvt ltd firm

Hello Sir,

Is it must to be appointed as a additional Director instead of directly appointing as a Director in Pvt. Ltd firm?

if yes!

1. What will be implications on powers/rights of a "additional director" in organisation?

2. What will be implications on share holding of "additional director"?

3. How long it should take to change desiganation as "Director"?

4. can there be any kind of negative aspect of the same on "additional directors" growth in organisaiton?

Many Thanks in advance.