Using MOD with Time values to determine time differences that transition midnight - excel

Question

I created an Excel Spreadsheet with a Total Time for the Duration of the Shift ie 8:30-17:30.
Then I created this formula
=(MOD([#[Supposed Shift End]]-[#[Supposed Shift Start]],1))*24
with Format cells -> Number 2 decimal places. This gives me the [Total Supposed Shift Hours]
Giving me Duration of the Shift that needs to be covered.
Now I also created another column for the ACTUAL time the shift covered
=(MOD([#[Actual Time End]]-[#[Actual Time Start]],1))*24
This gives me the [Total Actual Time Hours]
For the Actual Time End and Actual Time Start When the employee DIDN'T show up we entered 0 for both cells with the same cell format Number -> 2 decimal places
The Problem:
This is the formula I wrote to subtract these 2 Columns
=(MOD([#[Total Supposed Shift Hours]]-[#[Total Actual Time Hours]],1))*24
Why when I subtract say the [Total Supposed Shift Hours] 9.00 - the [Total Actual Time Hours] 0.00 = 24.00 ???
9 - 0 = 9 not 24.... sigh
Will the formula be affected if the time goes from previous night 21:00 to 8:00 with the MOD formula?
Sample data (as requested)
Note: Nomenclature differs from description above: Open = Supposed and Covered = Actual
Service Date
Open Post Start
Open Post End
Total Hrs Missing
Covered Post Start
Covered Post End
Total Hrs Covered
Category
Hours Not Covered
02/06/2021
16:00
00:00
8
16:00
03:00
11
A
0
04/06/2021
16:00
00:00
8
00:00
00:00
0
A
0
10/21/2021
10:30
00:00
13.5
18:00
19:30
1.5
B
0

Answer 1

Initial Answer
A minor point first: You don't need to wrap the MOD function in brackets. As the function already produces a result to the *24. Thus the following works just fine:
=MOD([#[Supposed Time End]]-[#[Supposed Time Start]],1)*24
To your question: Your non-working formula reads as if it simply wants the difference (in hours) between Supposed and Actual. If that's so, simply do this:
=[#[Total Supposed Shift Hours]]-[#[Total Actual Shift Hours]]
EDIT: Using the (now posted) table, I've constructed what I think it is you're trying to doRefer to Sample results image below.
Formula in Colum E: =MOD([#[Open Post End]]-[#[Open Post Start]],1)*24
Formula in Colum H: =MOD([#[Covered Post End]]-[#[Covered Post Start]],1)*24
Formula in Colum J: =[#[Total Hours Missing]]-[#[Total Hours Covered]]
Sample results:
Now: If Column J (i.e. the response to your core question) isn't the result you're after, can you tell me what it is you would expect there (using actual expected values for each row).
Notes:
Your table column header Total Hours Missing is somewhat confusing.
But, I'm reading that a Post Duration (Duration of Shift in your original parlance).
If I understand what transpired correctly, the "spanner in the works" was #P.b suggestion to remove MOD. Revert your formulas in columns E and H as shown above.