Formula formatting query

[alan peele]

I have a formula that is causing some frustration and am looking for some assistance please.

I have a spreadsheet that calculates the available hours per shift I am expecting at work per day. This formula works ok, but because some of the shifts cross the 24:00 mark, the cells are formatted in a specific way.
I am trying to get the output from this cell to pick up automatically into another cell, which is in itself, one link in a formula, but the formatting required to achieve the correct result in the original cells, seems to be corrupting the formula in this second string.
Any ideas?

I have attached a copy of the spreadsheet just in case my explanation is poor.
Thanks for any advice.