Good question - yet I think I addressed this in the tut.
However, CellR means NEXT row relative to current row...
ie. CellR(0,1) means put stuff in current row (col 1)
CellR(1,1) means put stuff in the Next Row (col 1)
whereas
Cell(1,1) means put stuff in row 1
There are so many options when dealing with the grid