RTL Utility has been updated to v0.4.0. This update corrects a problem which saw incorrect measurements for some interfaces (e.g. low measurements for RME Firefaces).

EDIT: We've since updated to v0.4.1 which improves speed of measurement for some interfaces (including RME Firefaces).

It is recommended that you update to this version and retest your interface.

Download latest version from here.