Is data pump import completion time increased with flashback logging

Hello all
Our sys dba enabled flashback logging on our test instance (10.2.0.4.0).

Our import times have now almost doubled.
We frequently refresh schemas in our test environment with production data
We use OEM version 10.2.0.5.0 , -> Data Movement -> Import from Export File.

Is the flashback logging increasing the import completion time?
If so, is there a setting to disable flashback during the data pump import?

thanks
Ken