Rated 3 out of 5 stars

1) Extract .xpi
2) Go to chrome\content\styles.css
3) Add to bottom of file and save

/* <<= FIX AUDIO JUMPS */
.audio.over .duration { display: block !important; }
.post_media .audio .actions { background: #FFF !important; padding: 0 15px !important; }
.post_media .audio .actions .audio_add_wrap { margin: 4px !important; }
/* END FIX AUDIO JUMPS =>> */

4. Pack .xpi
5. Remove old extension from FF and restart
7 Open (CNTR+O) and install new .xpi
8 Done

This review is for a previous version of the add-on (0.3.8.1.1-signed).