> A $100M fund which does 4x earns the GPs $80M ($in carry, plus $20M in management fees)
Nope. 2% of $100M is $2M, not $20M.
> A $1B fund which does 1.5x earns the GPs $300M ($100M in carry, plus $200M in management fees)
Nope.
It's 2M x 10 years (for each year of the funds life).
Ditto for 20M (x 10 years)
> A $100M fund which does 4x earns the GPs $80M ($in carry, plus $20M in management fees)
Nope. 2% of $100M is $2M, not $20M.
> A $1B fund which does 1.5x earns the GPs $300M ($100M in carry, plus $200M in management fees)
Nope.