Editing a formula to accomodate new information

Hi, In my spreadsheet (attatched) the small table to the right creates a monthly total for incoming daily payments which are detailed in the main table on the left. (this is a different total to the weekly totals as the weekly totals do not allow for months which finish mid week).

I have just inserted a new column (C) I would like the figure in this column to contribute to the monthly total in G4.

I got some help from this someone on this forum to create the formula in G4 and now I cannot figure out how to change the formula in G4 (and downward for further months) to include the new payments now being detailed Column C.

I hope that makes sense, and i hope someone can help.

My suggestion would be to use SUMIFS() instead of SUMPRODUCT() so it would be:

=SUM(SUMIFS(B:B,A:A,">="&F4,A:A,"<="&EOMONTH(F4,0)),SUMIFS(C:C,A:A,">="&F4,A:A,"<="&EOMONTH(F4,0)))
in G4 and down
and replace the SUMPRODUCT() in H4 with:

=SUMIFS(D:D,A:A,">="&F4,A:A,"<="&EOMONTH(F4,0))

you can change the whole column references to specific ranges if you like