meaning of ampersand in spreadsheet cell references

[Adam Spiers <orgmode@adamspiers.org>]

Hi all,

The manual refers fleetingly to the use of ampersand in spreadsheet
cell references.  Amongst other cell reference examples, it lists:

     $5        column 5 in the current row
     E&        same as previous

The only other mention I can find is:

  When offering a formula for editing, Org converts references to the
  standard format (like `B3' or `D&') if possible.

I assume this means that ampersand can replace the number in cell
references of the format `B3' to means "the current row"?  However
this doesn't seem to tie in with any of the other syntax listed, and
therefore maybe warrants a slightly more explicit explanation in the
manual?

Thanks!
Adam