sum time over 24 hours with a twist

[mkelly]

I am currently using this formula to calculate total time worked that exceeds 24hours:

=Int(Sum([job completed time]-[job start time]-CDate("0:0:" & DatePart("s",[job completed time]-[job start time]))))*24+DatePart("h",Sum([job completed time]-[job start time]-CDate("0:0:" & DatePart("s",[job completed time]-[job start time])))) & Format(Sum([job completed time]-[job start time]-CDate("0:0:" & DatePart("s",[job completed time]-[job start time]))),":nn")

My question is can I change this to calculate only the time in the records that include a [work type]="Dup-1"

So that I am only calculating the time for the Dup-1 jobs for the date range of the report.

All help appriciated.