Additional miles will not be earned for bookings that are subsequently upgraded to a higher class whereby an additional fare difference is paid. (virginatlantic.com)
If a Member upgrades to a higher cabin of travel by means other than by paying the full fare difference between the original fare class ticketed and the new higher cabin fare, the Status Credit earn rate for the original fare class ticketed will be applied. (velocityfrequentflyer.com)
Changes and cancellations incur a fee and any applicable fare difference, see Virgin Australia's Fees page for details. (travel.supercars.com)