DPM 2010 might be wasting storage pool space if you don't calculate data size of protected members you add

I was configuring some backups when I noticed that the available storage was decreasing rapidly and I don't have that much data yet
I went back to the check the disk allocation for the new members I created and I found that DPM has allocated several gigabytes to backup some hundred megabytes and retain just a few days.

Shrinking and recalculating did not work. So I stopped protection and added them back.
When I calculated the data size during the protection group wizard it allocated reasonable sizes for the replica and recovery point volumes