So far I found I can use this, in column E.

=IF(C3<=D3,"+ ","- ")&TEXT(MAX(C3,D3)-MIN(C3,D3),"[m]:ss")

To display negative time, whereas before I was using,

=IF(D3="","",D3-C3) to leave the column E blank.

The 2nd one was good because it would leave the column blank until I made an
entry in D, is there a way to use the first Formula and leave the column
blank?

Also I'm using Sumproduct on another sheet to count the entrees in E.

Here is an example.

In B,
=SUMPRODUCT(--(LEFT(LTC!$F$3:$F$192,4)=OTP!A8),--(LTC!$E$3:$E$192<=--"0:10:59"),--(LTC!$E$3:$E$192<""))

In C,
=SUMPRODUCT(--(LEFT(LTC!$F$3:$F$192,4)=OTP!A8),--(LTC!$E$3:$E$192--"0:10:59"),--(LTC!$E$3:$E$192<""))

When I use =IF(C3<=D3,"+ ","- ")&TEXT(MAX(C3,D3)-MIN(C3,D3),"[m]:ss") , the
sumproduct formula will count all entrees in C, --"0:10:59"

Is there a way to make these 2 sheets work together?

I need anything negative and up to 0:10:59 in column B, and over 0:10:59 in
column C.