Hi! So the watch was set at 22:05 when the time was actually supposed to be 20:55 (inverted). So the time difference would be 1 hour and 10 minutes between them.
So then he woke up in the morning and saw 10:09 on the watch however the real time would be 1 hour and 10 minutes before than which would be 8:59. Inverted it would show E: 92:80. You have written 2 but when 2 is inverted it should read 5!!
Hope this helps!