Hi Steve,

I'm not sure I have the expertise to help and I'm still not clear
about your desired outcome. Here are some questions they may clarify
your goals for the group to offer some help.

Do you want a macro to write the formula to all the rows in 800
workbooks?

Are all the workbooks laid out the same?

If you got this to work, what would that do for you?

I hope this helps,

Dan