The PURP is not realised profit. Profit for the group is only realised if the goods have been sold outside the group.
If there is inventory left in one of the group companies that was bought from the other group company then there is unrealised profit – the group cannot take credit for the profit made by one company selling to the other company unless those good did end up eventually being sold outside the group.
Have you watched my free lectures on this? The lectures are a complete free course for Paper FA and cover everything needed to be able to pass the exam well.