[Orgmode] Spreadsheet question

[Tassilo Horn]

Hi all,

I have this table:

| header |
|--------|
|      1 |
|      1 |
|--------|
|      0 |
#+TBLFM: @4$1=vsum(@address@hidden)

The cell containing 0 should sum up all values of the column's rows
above.  But C-u C-c C-c gives 2, then 4, then 6, then 8...

Reading the docs I found out that @-1 won't cross hlines, so now I use
-I instead which works.  But still I don't understand the @-1 behavior.
Even if knowing that it doesn't cross hlines I'd expect it to calculate
the correct value or at least error because there's no row above @4
before the next hline.  So why is (equal @-1 @0) here?

Bye,
Tassilo