I am confused what the issue it?
A PO is for a material and plant combination.
The PO may have multiple materials in it.
But the quantities are per material.
So why do you say the PO in ECC is for 100 units?
You meant to say you have a PO in ECC that is for 75 units of material 1 and 25 units of material 2?
A PO does not show as InTransit in APO. A PO is a PO. It shows up as Distribution Receipts in APO.
Is the issue with PRoduct View /sapapo/RRP3 or your Planning Book.
You created the Planning Book so we can't debug your planning book.
CIF will not combine the quantities for 2 separate materials into a single material.