My grandmother is flying on CX252 (747) LHR-HKG in the near future and I'm trying to select some good seats for her, however the seatmap displayed by QF is completely confusing me:

Seats A, C, H and J in rows 30 through 33 are obviously appealing due to the 2-4-2 layout, but I cannot for the life of me work out why there would be 2-4-2 Y seating in the middle of the main deck of a 747, nor why the 2-4-2 layout would only be available for 4 rows of the cabin. I cannot find a single seatmap online which reflects this layout (SeatGuru, SeatExpert, etc), nor can I find any discussion on forums about these seats.
Can anyone shed any light on this for me - is the seat map correct? Why would it be 2-4-2 for rows 30-33? I've checked EF and it is also showing the same seatmap, albeit showing all the seats in rows 30-33 as taken (which is also confusing, unless it's got to do with this booking being on FF points via QF and my OWE status is playing a role in available seats via QF but not via EF).
Thanks.
EDIT: Of course, just after posting this, I stumbled across this article: http://www.ausbt.com.au/cathay-pacific-refits-boeing-747s-for-premium-economy-new-economy. It mentions CX launching a new four class 747 layout from 01/05/2012 on exactly the route my grandmother is flying, and says that the PE cabin is rows 30-33. The number of PE seats (26) mentioned also lines up exactly with the number of seats in rows 30 through 33 on the above seatmap. Has my grandmother somehow lucked out and can select seats in CX's new 747 PE cabin despite being on a Y ticket?

Seats A, C, H and J in rows 30 through 33 are obviously appealing due to the 2-4-2 layout, but I cannot for the life of me work out why there would be 2-4-2 Y seating in the middle of the main deck of a 747, nor why the 2-4-2 layout would only be available for 4 rows of the cabin. I cannot find a single seatmap online which reflects this layout (SeatGuru, SeatExpert, etc), nor can I find any discussion on forums about these seats.
Can anyone shed any light on this for me - is the seat map correct? Why would it be 2-4-2 for rows 30-33? I've checked EF and it is also showing the same seatmap, albeit showing all the seats in rows 30-33 as taken (which is also confusing, unless it's got to do with this booking being on FF points via QF and my OWE status is playing a role in available seats via QF but not via EF).
Thanks.
EDIT: Of course, just after posting this, I stumbled across this article: http://www.ausbt.com.au/cathay-pacific-refits-boeing-747s-for-premium-economy-new-economy. It mentions CX launching a new four class 747 layout from 01/05/2012 on exactly the route my grandmother is flying, and says that the PE cabin is rows 30-33. The number of PE seats (26) mentioned also lines up exactly with the number of seats in rows 30 through 33 on the above seatmap. Has my grandmother somehow lucked out and can select seats in CX's new 747 PE cabin despite being on a Y ticket?