è proprio vero, guardate il regolamento sul sito della CEV, è in inglese ma dice così
During the Playoffs in which single home and away matches are played, the
following rule/procedure to determine the winning team will be applied:
Each team will play one home and one away match. The team qualifying for the next
round is determined by the results of matches on the basis of matches won and lost.
In case of a tie – 1 match won, 1 match lost and no matter whether the matches finish
3:0, 3:1 or 3:2 – the opponents have to play one extra set, called golden set.
questo il link (a pagina 28)
www.cev.lu/mmp/online/website/main_menu/...tions_2010_09_13.pdf