I'm not 100% sure what you are asking so I'll answer both possibilities.
When a member gets placed on vacation, 24 hours are removed from their vacation bank. If that member comes off of vacation before the 24 hours have elapsed, the difference in the time taken is added to the clock in any games where the player is on the move, up to the time control.
The second thing is that members get vacation days added during the month. So additional days get added. How many depends on premium level.
Hi
in game https://www.chess.com/echess/game?id=136190842 we can find holiday calculation error - algorithm adds 2 day, once about 20d, second few hours ago - looks like the holiday is 4 days longer. Who can fix the algorithm?