I would start by creating a shared variable and give it the value of 1/1/1900 (because this is zero in SQL Server). Then for every detail line, I would add the amount of work/travel performed using date add,probably in minutes, (this would probably be suppressed or hidden). In the summary line, you would now have a date, which I would display something like:
shared numbervar worked;
local numbervar idays := day(worked); //will give the number of days
totext(idays*24,0,"") + totext(worked, ":mm:ss")
HTH
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