Nick - Unlike Spreadsheets, Omniscope does not have a fixed way of referencing rows, only columns. This means that formulae referenecing rows like repeated observations over time are more restricted than those that can be expressed in spreadsheets. If the Values to be summed can be strictly ranked in order, and the running subtotal required in any given row is a fixed number of records, say past 6 months, there is a way to do this. However, it is not open-ended, i.e. you cannot do all values since inception of the time series. E-mail me if you want to see the file/formluae for ranked running (fixed interval) subtotals.

Please see this posting for a way of hacking up a running total using SUBSET functions:
http://forums.visokio.com/comments.php?DiscussionID=453