I just created a 'projection' node and then created a new calculated column and changed the decimal sizes of "12.3(15) of QUANTITY" to 17,3 and "11.2(13) of SUBTOTAL" to 17,2 since those were the decimal sizes in the replicated BW tables and this solved it.
Will keep this discussion 'open' for sometime to see if there's a different solution to this and to confirm if my solution is the right approach.
Thanks,
Benedict