BB vs SB open stats

[nprodromidis]

In my hud i have these 3 stats :
BB vs SB open - call
BB vs SB open - fold
BB vs SB open - 3bet

I would expect the total instances (the denominator)to be the same for all three.
It appears that its the same only for the "CALL" and the "FOLD"
The "3-bet" has a lot less counts.
Why is this the case?
Does this has anything to do with how i display the HUD for number of filtered players in the HUD-options?

[Flag_Hippo]

In hands where the SB opens with an all-in the BB can only call or fold.