Any reduction does seem very odd - I would cross-check and as Tony suggests, ask the Pensions Team for an explanation. Have they missed a transfer in value, for example?
My HPS2 statement came thru last week, indicating the inflation increase since leaving and separate transfer in value, which all seemed correct and well presented so I could follow everything
I also see that we get CPI (with limits) on that deferred benefit until NRD on the whole lot. Whereas I had thought pre-1997 benefit would get zero indexation from date of transfer to HPS2, but actually this only starts from NRD itself. So that was (marginally) better that I was expecting.
Of course, no more 5% & RPI as it once was...