I have been using this formula {which is working fine}
SUMPRODUCT( N( MOD( COLUMN( $I37:AJ37)) -6, 7)= 0), $I37:AJ37) +F37
where the first part creates a mask for every 7 column, Middle part is numbers, text and blanks which only every 7th is needed, and the last part is a offset value. I...