Time probs again

[Parkypark]

Firstly thanks to all whio have helped my before
But I am back

I have a date time field that is worked out via adding time to an arrival field but it is different depending on priority
eg
if {HPD_HelpDesk.Priority}= 'Critical' then {HPD_HelpDesk.Arrival Time} +(10/1440)
else
if {HPD_HelpDesk.Priority}= 'Urgent' then {HPD_HelpDesk.Arrival Time} +(1/24)
else
if {HPD_HelpDesk.Priority}= 'High' then {HPD_HelpDesk.Arrival Time} + (4/24)
else
if {HPD_HelpDesk.Priority}= 'Medium' then {HPD_HelpDesk.Arrival Time} +1
else
if {HPD_HelpDesk.Priority}= 'Low' then {HPD_HelpDesk.Arrival Time} +2

my problem is I need this formula to only count during business hrs of 0900 - 1700

I have tried to add a business hrs formula but it returns a value in hrs not a date time value like i want

Please help.

 

[Parkypark]

I have tried to integrate a kenhamady business hrs formula, but this does not seem to work.

I am not doing something that I should be I guess