I did not follow exactly your example, I wanted to explain the difference between intra-company and external procurement.
Of course you cannot receive another 50 if you have not shipped them, this is just proving what said, in intra-company scenario it is a very tight business case with a field for in-transit stock at MARC record.
in inter-company the in-transit stock is just virtual, no quantity in the MARC field. It is just a calculated difference between issued and received when you see it in MB52 or MB5T reports.
This process is closer to the external procurement process (vendor in the header instead of plant) and this allows to receive a quantity even before it was shipped.