Ages ago I was involved in the first installation of a King KFC 150 (I think) on a PN68. The duch King engineer told me then that the A/P and F/D used the same computer. On the 727 I fly today there is definitely 2 different systems. The A/P requiring re-sensitizing of the GS in 1500' AGL, the F/D does not require re-sensitizing.