Werner - I'm not sure your tests are reliable. They may depend on the
order you enter formulas, e.g. if you enter the formula i proposed
above and then restore the original sum(name) formula, it does
recalculate ok. (Maybe something to do with the calculation tree not
being rebuilt?)

To be safe, I would try a solution along the lines Charles' suggested
although I think you need to use N(offset(...)) to dereference the
array.