Hi All,

I have one requirement of caliculate the business hours of case first touch by rep, for this i created 2 fields 

1. First touch date (Date time filed)
2. Business Tat hours. (Formula filed)

when ever a case is changing the staus from New to other statuses i am updating first touch date with system.now() in trigger. then after i am using this formula to get the business hours calucation based on case created date and first touch date. here is the formula 

ROUND( 8 * ( 
( 5 * FLOOR( ( DATEVALUE(First_Touch_Date__c ) - DATE( 1900, 1, 8) ) / 7) + 
MIN(5, 
MOD( DATEVALUE(First_Touch_Date__c ) - DATE( 1900, 1, 8), 7) + 
MIN( 1, 24 / 8 * ( MOD( First_Touch_Date__c - DATETIMEVALUE( '1900-01-08 16:00:00' ), 1 ) ) ) 
) 
) 
- 
( 5 * FLOOR( ( DATEVALUE(CreatedDate) - DATE( 1900, 1, 8) ) / 7) + 
MIN( 5, 
MOD( DATEVALUE(CreatedDate) - DATE( 1996, 1, 1), 7 ) + 
MIN( 1, 24 / 8 * ( MOD(CreatedDate - DATETIMEVALUE( '1900-01-08 16:00:00' ), 1) ) ) 
) 
) 
), 
0 )


Now the issue is when a case is created between 12.00 AM to 8.30 AM. and first touch date is that case created date then business hours is caliculating negative values. here  Case is opened at 8/9/2016 4.15AM  and First touch date is  8/9/2016 4.53 PM then my Business Hours(TAT) should be 8 hours 23 minutes, but it is showing -3.00 hours as negative value with above salesforce provided formula. how should we reslove this with formula field.. 

here are my business hours. 





How should i resolve this issue any help is appreciated.

Thanks