I have numerical data in columns A & B that SUM to C ie C1=SUM(A1:B1)

Now I have a macro that inserts a column between B & C. However the sum does not take into account this column and ends up attaching an error comment that 'Formula Omits Adjacent Cell'.

I am looking for a way to include this inserted column automatically within the macro so I don't have to go to each error message on each row of COLUMN C and manually fixing it.

How can i extend this range?

I know that one can use ActiveCell.FormulaR1C1 = "=SUM(RC[1]:RC[3]) however each time my macro is run a new cell is inserted and hence the above is well under range

Many Thanks