Subtracting hours in a work schedule

Just when I thought it was over....that's what I get for thinking.
Sometimes, the Boss (yeah, the pain in my butt one...LOL) has split schedules for days of the week. I will try to explain:
1 person may need to open the store in the AM, leave for the afternoon then, close the store in the PM.
The hours usually run as follows:
8:15 am - 12:00 pm then 4:00pm - 9:15 pm with no 30 minute lunch break deduction. (9 Hours total for the day)
or
9:00 am - 12:00 pm then 4:00 pm - 9:15 pm with no 30 minute lunch break deduction. (8.25 Hours total for the day).
I have tried vlookup, sum and others but as usual I can't come up with anything that does not return an error.
When we input the "hours" for a split day, maybe it can just be typed in as "split 1" that starts at 8:15 am and "split 2" starts at 9:00 am and it can somehow reference the hours from a vlookup and calculate the proper hours in rows D,G,J,M,P and S. Then, calculate the total in row T and following up with the Grand total in row X.
In this formula, it does not need to calculate Day and Night shifts as seen in rows AB and AC since it is both.
I am so lost with this one!!!
Thanks for any and all help anyone can give. I am attaching the file for reference.
Laura