The performance in flight section of the QRH only contains data for the -800, and then only in kilograms. Why?

I thinks that in QRH PMDG won't like overload with data performance, and shows only a aircraft type (when the 737NGX was delivered only was -800 and -900).The data is in kg maybe is the international unit system.You can find the QRH performance information complete for all aircraft variations in FCOM 1 of page PD.TOC.30.1 to final document (about 600-800 pages).See ya!