Trying to add to an existing formula to leave cell blank depending on value of another cel

My boss is under the impression that I am an EXCEL expert, but I'm really close to proving him wrong. I have made a bunch of changes to an old spreadsheet for him, but I am stuck on the final bit. I need to add to a couple of formulas to cause them to return a blank cell based on the value of another cell. I have tried every iteration that I can think of but continue to fail. I have attached a copy of the sheet.

The problem is that one of the sheets is looking for time values to sum and all of the extra data is really throwing off the numbers.

Example:

=IF($B$24<>0,$B$24+TIME(0,L$85,0),"")
I would like to add a formula to return a blank cell if L6 is either blank or contains a zero.

The same with this one: =IF($B$12>1,IF(L$7<>0,L7+TIME(0,$B$15,0),""),"")

I feel like this should be simple to do, but my brain is now officially fried.

Any assistance would be greatly appreciated.