TDE starts on vt8 after power outage

When reading the thread "Lockups after unlocking screensaver", it reminds me an unanswered question I had months ago. I use Trinity 3.13.2 on Ubuntu 12.04 LTS. As far as I can recall (years), my TDE session started on vt7 (Ctrl-Alt-F7). After a power outage, I restarted my box and ever since TDE starts on vt8 (Ctrl-Alt-F8). Everything works well but I would like to understand the reason of this vt switch. I searched the web for an answer with no success. Does someone on this list has an answer? Nothing harmful, no bug, but curiosity... is on mars now :-) midi-pascal