This 3-4-3 seating is an interesting strategy.
I think overall, PR wants to compete against both the LCCs (e.g., 5J), and many legacy carriers. Not that 5J has ULH flights to the USA. But I can see why they are 'cheapening' their economy offerings. It really widens the gap between Y and PEY.
It is really interesting how the 35Ks have a modern C and PEY, but with a super tight Y; while the 77Ws remain with an outdated C, no PEY, and a standard tight Y. I guess many Philippine passengers do not mind the inconsistency???