Calculating a total of a column Livecyle EC2

I am using sum the following script

sum(Table1.Row1[*].amount[*])

to total 28 rows in a column however the script only seems to work on Row1 - I am not sure what I am doing wrong -

I am using formcalc and each cell is labelled 'amount' and is a numeric field.  The script is entered in a numeric field labelled Total.

I feel I am missing something simple but not sure what.

Can someone help?