How to create a formula in numbers that calculates the duration of music between two timecodes? (Cue Sheet)

Hello,

I'm a screen or film composer filling out my first cue sheet in numbers and I would like some help with creating the appropriate formula.

I was able to create a cell format for Timecode In and Timecode Out HH:MM:SS:FF (FF standing for 24 fps,) following someone's post to this community, but now I want to create a formula which subtracts Timecode In from Timecode Out to give the total duration as a result in the next cell.

I'll attach the link to the post I used to create the HH:MM:SS:FF format for reference:

Numbers: Cell format for Timecode (Cue Sh… - Apple Community

Finally, if there is a way to make the result in HH:MM:SS only, (without frame rate at the end,) that would be ideal!

I'll add a pic of the numbers cells for reference, the result of the duration should go in the final cell with the red triangle in:

I would really appreciate it if someone is familiar with this, and hopefully this thread can be helpful to others as well.

Thanks for everyone's time in advance,

Hope all of you have a nice day!