Audio level difference between unimported assets and UE4 output

Hey there,
I noticed that there is a significant difference between the audio levels after importing assets to Unreal.
I have gunshot assets that peak at -0,5dBFS. After importing them to Unreal, they peak at around -9dBFS.
Where does that difference come from? I wasn’t able to find any settings related to this matter.
Thank you in advance