Avoid OFFSET and other volatile[0] functions in Excel. Use things like INDEX instead.<p>[0] Volatile functions are those whose value can be affected by a large number of other cells, and Excel doesn't know which cells until it evaluates the function. So whenever <i>any</i> cell's value changes, <i>all</i> volatile functions must be recomputed. This can cause a ripple effect, too, making your spreadsheet grind to a halt or take hours to become responsive.