Pokemon Ghost Pokemon easier to catch?

[pichu brothers]

Acording to Serebii, the catch formula is:

(PokéballEffect)*((((4*[MaxHP]-2*[ActualHP])*[CatchRate]):[MaxHP])+Status+1):256

Normal PokéBall Effect: 1
Greatball Effect: 1.5
Ultraball Effect: 2
Masterball Effect: Infinite
Timerball Effect: ((Turn N°+10):10)
Duskball Effect: 4 (night), 1 (otherwise)
Quickball Effect: ((50-Turn N°):10) (unsure)