auto calculate lunch break

I'm having a bit of a problem with writing this formula.

When an employee completes a daily Time card to record their hours the select the project and times they worked.
Example:
Date                   Name         Project                 Start Time                 Finish Time      Total Hours
9/12/2019         John D.     0001                    6am                           8am                      2
9/12/2019         John D.     0007                    8am                           3pm                     7
9/12/2019         John D.     0004                    3pm                           5pm                     2

As you can see John worked on multiple projects in one day.  This information is important for two reasons; 1)Hours for how much to pay the employee, and 2) how much expense is being charged to that project.

So, I am trying to auto assign lunch to the correct spot.  Lunch break is required if you work more then 5 hours in a day.

this is my formula

if([Start Time]<12 & [Finish Time]>12 & ToHours([Finish Time]-[Start Time])>5,
     ToHours([Finish Time]-[Start Time])-.5 & [Lunch]=1,
     ToHours([Finish Time]-[Start Time])
)

[Lunch] is a checkbox

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Russell Beaubien
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