I need to calculate a Duedate and time based on Production Hours, on workdays and specific work hours.

Basically:
Start Date/Time: (or actually ending time order before this one)
2016-11-15 09:00 (First entered manual)

Amount of hours for production: (entered manually)
15

Workday start (needs to be flexible):
07:00

Workday end (needs to be flexible):
16:00

And I need to get out:
Finished Date/Time:
[Automatically Calculated]



If it is possible it would also be great if it was possible to just enter the next cell underneith with the same formula to get the next product in line calculated etc.


Any ideas?



/Jocce