"jamesplaw" wrote:
I am currently using the formula (below) in row '29'. The
formula is specific to column 'B' for total in 'B29'[....]
Currently I am having to retype the formula for each new row
I add and I am pretty sure the formula is in a 'bad' format.
"=L15(B3*$I$3)+(B4*$I$4)+[....]+(B24*$I$24)+(B25*$I$25)"

I don't know what operator is missing after L15, but you might try something
like:

=L15*SUMPRODUCT(B3:B25,$I$3:$I$25)

If you are careful to __insert__ rows after row 3 and before row 25, Excel
will adjust the ranges in the formula automagically.