Hello everyone and I hope someone can help me on this. I am working on
a spreadsheet and I am trying to automate some of the calculations in
the document I am running into a sticking point and I wanted to see if
anyone has an idea on how to get this to work.

Issue:

I am receiving data from an exported report that works within Excel.
It has a date and timestamp plus some recorded data associated with
that timestamp. What I have going on right now is I have the
following columns in the export.

| Device | SubDevice | Date / TIme | Reading_1 |

What I have set right now are three columns to the right of the
reading. They look at the data in each reading column and apply the
following. The first column looks at Reading_1 and sees if it is above
a threshold, if so it labels it with a Y (named: #). The second
column looks at that same Reading_1 and if the number is below the
threshold it tags it with X (named:<#). A third column does an "ifand"
which says if the previous # reading is a Y and the current <# is a X
to mark third column clear (named: ok). What I am trying to do is take
these columns in someway have them calculate the difference between
the start and clear times. Basically I am looking to see if there is
way to automate a calculation that looks at the ok column and if it
shows ok to subtract that value from the last ok reading. So if it
happens 20 timestamps back, excel finds it and makes the calculation.
Any thoughts on how i can do this? Thanks!