Had a look at some seat maps for an upcoming flight, and it seems like the 'Preferred' seating includes all of the upper deck on a 2-class A380 and all of the front cabin of the lower deck (which is interesting if both lower deck doors are used for embarking/disembarking, as the second Y cabin can often get off fairly quickly too).
On a 2-class 777 it seems like it is just rows 8-12 that have been blocked. I'm not about to test this out by deselecting my seat that is currently amid the twins!
On a DXB-UK, 2-class 777:
- a preferred seat is $40
- a twin seat is $55
- a extra-legroom seat is $95
On a UK-DXB, 3-class A380:
- a preferred seat is $40
- an extra-legroom seat is $95
On DXB-KUL, 2-class A380:
- a preferred seat is $40 (lower deck) and $55 (upper deck)
- a twin seat $80 (upper deck only)
- a extra-legroom seat is $95 (lower deck only)
While UK-DXB and DXB-KUL (or SE Asia) fall into different Skyward redemption brackets (despite being of almost similar stage lengths), the seat fees seem to be the same.
What is frustrating is the added complexity this is all bringing - four types of seats (each priced differently), with different entitlements based on fare type, and further variations based on Skywards status.
As a solo traveller I can't imagine forking out for any of these. The added value of Silver over the past year, in being able to snag the twins on a 2-class A380 or 777, seems like it has gone for me now - there's little difference between the rest of the 'regular' seats if that is the sole Silver benefit when it comes to seat selection.