MfgConsoleFunc Expression related papyrus issue

[coldloc]

I have one puzzle related with below function MFGConsoleFunc.psc

 

; return expression value which is enabled. (enabled only one at a time.)
int function GetExpressionValue(Actor act) global

(  illustrated in the 2nd mapping relationship in screenshot ,  expected to be value 60 instead of 0  )
It seems not getting me the correct value,  anyone has any ideas or have met similar issues before ?

 

 

 

also noticed that when i 
npc.SetExpressionOverride( eID , eValue ) 
do set method, if the  eValue is == 0  ,  the expression won't be set even if the eID has valid value  , result becomes  -1,  0