Upgrading with miles
I am looking at possibility of upgrading two segments of a three segment trip (australia-sq-singapore-sq-europe-europe). I have not purchased a ticket yet but have found the upgrade description on the booking page and although it says upgrade is allowed, when the information button is clicked it states "We are unable to process your request. Please contact your local Singapore Airlines office to find out the number of miles required for your upgrade."
If the final non-sq sector is removed and I search for the first two segments only, the information button lists the number of miles as expected from the upgrade chart.
Does anybody know if the presence of a non-sq sector in the booking would prevent an upgrade to the sq sectors?
Thanks