# Difference between specific value in one row with negative value and specific value in next row with none-negative value!

Ah hello.

This is a continuation of a previous question.  In my attached sheet, I have a series of S and A values representing a TCP conversation.  The A-S column shows the difference in values between the last "S" and the current "A" value.

What I need to do is automatically calculate the time difference between a row that has a negative A-S value and the next row that has a none-negative "A-S" value.

So, if we look at D11, we see we have a negative A-S value.  The next "A-S" value that is none-negative is that in D13.  The difference in TIME between D11 and D13 is shown in E13.

TIA
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Commented:
Try this in E2 and copy down
``````=IF(D2<>"",IF(INDEX(\$D\$1:D1,LARGE(INDEX((\$D\$1:D1<>"")*ROW(\$D\$1:D1),,),1),1)<0,B2-INDEX(\$B\$1:B1,LARGE(INDEX((\$D\$1:D1<>"")*ROW(\$D\$1:D1),,),1),1),""),"")
``````
See sheet.
Start.xlsx
1

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