Hi Neeraj,
Please note that any inter-company postings that are different from the invoicing flow might be illegal. I am not familiar with any situation when postings between legal entities are allowed through CO module cost allocation. That is very much from the past or when multiple Company codes belong to the same legal entity. You cannot get cost or revenue out of nowhere into the company P&L without a single legal document.
So, I would be very very surprised if your scenario was accepted by accountants in both USA and Colombia...
In my sample scenario every legal entity that provides own resources for the US project will need own WBS-element. The advantage of such project is that you have a full cost/revenue picture at any time, not just at month-end. It is a global project where different WBS-elements belong to different Company codes.
"Someone will manually transfer...", - no. You cannot manually transfer anything between legal entities. It will be an RRB from one WBS to another US WBS at any agreed interval, month-end or weekly or whatever agreed.
Next there will be a second RRB from US part of the project to the external customer.
Regards,
Paulo