Good point. It would appear at this stage though that the 12% contribution for DC applies to the current "Pensionable", giving the 9% approx of basic. I think negotiations are likely to be on going. However, the NAPS "Pensionable" at the top end of the scale is close to Robber Brown's pension cap so if pensionable pay was increased, it would probably become illegal. I'm no way expert enough to how this would effect the new DC scheme, although I'm willing to bet a DC pension would be no where near the pension cap. However, there would probably be murders if the DC scheme was based on a higher rate of pay than NAPS.
Unfortunately, it's a very complicated issue with no easy answers.