Calculate time elapsed, excluding time not spent working

I am needing to format a chart so that I can easily calculate the time it took to complete a truck load for my job. It is easy enough to do if the truck load is finished in one shift, however, I have run into this issue, any truck started one day 1 and finished on day 2 does not show a true time spent loading.

I need to be able to pass this information along in an easy to use way, with formulas already set, or the users have a high likely hood of not being able to use efficiently.

I tried splitting it up, since our shift ends at the same time and starts at the same time every day, but it ended up taking my time columns from start/finish to start/finish/start/finish.

=(O321-N321)+(Q321-P321) forumla I was using for the start/finish/start/finish but I would like to create something that would automatically take form 2:30 pm on any given day to 6:00 am the following day, the the dates were mot matching.
e.g. If a load is started 9/1/15 9:10 am & Finished 9/1/15 10:50, then the time spent loading is 1:40 (h:mm), but if the load is started
9/2/15 13:40 & finished 9/3/15 6:35 am, the time spent loading is 5:05, not 20:55 (because no work is being done from 14:30 to 6:00 AM)Shipping Load Report 2015 .xlsx (5).xlsx

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