Custom made calendar working in typical workday

Hi,

I have this data with a column "ERROR START" with the start date of my error, then the next column is "Time to fix" which is the time they have to fix it in hours, the last column is "EXPECTED FINISH" which present the latest date of when i expect the error to be done, within workings days, which goes from 8-16 each day (8 hours), so when they have 40 hours to fix the error it is technically 5 day (40/8).

I have created a datetime tabel which start 1/1/2017 and ends "TODAY", with a day lenght of 8-16.

Screenshots below.

Im using this formula to calculate the "EXPECTED FINISH":

But as you can see in the first screenshots it seems like it cant calculate it quite right when they have 40 hours to fix the error, but works fine when they have 8 hours to fix it. Anyone there know how to fix this?

AND is it possible to skip weekends (saturday & sunday), which means if i have a error start on friday 07/06/2019 12:00:00, with 40 hours to fix it, then the expected finish will be 14/07/2019 12:00:00 because it wont count saturday and sunday in, instead of an expected finish 12/06/2019 12:00:00 where it is counting saturday and sunday in.

Best regards ML