Your post doesn't mention what the MOD functions are doing, so I won't
attempt to address them; I mocked up data in cells A1:B4 to hold start
and end times, like this:
Work Start 7:00 AM
lunch start 11:30 AM
lunch end 12:30 PM
work end 5:00 PM

....and start / end calendar days for use by the NETWORKDAYS function
in B6:B7. I wrote this formula to get the total number of hours:
=NETWORKDAYS(B6,B7)*(((B2-B1)*24)+((B4-B3)*24))

Something I noticed about your post: you're using 9.5 hours for a full
day, but with an hour for lunch and those start / stop times, the
total is 9 hours.