Does this cut variance?

[Atropos]

Hey folks,
assume two players of equal MTT skill and play the exact same number of tournaments of the same buyin. They have an agreement to split their winnings 50%. Winnings are defined as payouts - buyin.

Here an example:
200$ Buyin, Player A busts, Player B cashes and gets 210$
--> 10$ are split 50% between them.

If they were playing on a shared bankroll, the variance would be reduced 50% it seems.
My questions is, how much is the variance reduced by this agreement, only splitting winnigs?