Soul Fragments and Soul Fragment Retrieval

Hi Team, I would like to clarify:

I had bought this field: Soul Fragments and Soul Fragment Retrieval. I just saw on the website today that there is also DM: Soul Fragment Retrival. If I already bought the first one, is it best to also buy the second one or is it the same?

This is not the same. The expensive one works stronger and faster, hence the price.

noted thank you!