I had a similar experience to you cantland.

I flew from Melbourne Intl (YMML) - Honolulu Intl (PHNL) a range of 4850nm. As I stated before, I had insufficient fuel. I'm not exactly sure how much fuel was remaining by the time I landed, but it was about 30%. By the time I was at the half way mark, I knew I was going to get there easily.

Autoland worked perfectly for me too. A pleasant flight was had by all.

It also appears to me to be a FMC problem.  :(

Mark