APP using VNAV:
"when appropriate,crews should make cold temp altitude corrections by applying a correction from an approved table to the waypoint altitude constraints.The FMC obtains the GP angle displayed on the legs page from the nav data base.This GP is based on standard atmosphere......If cold temperature alt corrections are not made,the effective GP angle is lower than the value displayed on the LEGS page.
When cold temp alt corr are made,VNAV PATH operation and procedure tuning function normally;however,the a/p follows the higher of the GP angle associated with the app or the geometric path defined by waypoint alt constrains.
NOTE: Temp corrections redefine the GP only if the FMC has the geometric path option installed."
from FCTM 5.41 (31 oct 4004)
this is for using VNAV to land,for ex instead of ILS. Not for using VNAV for app,then followed by a ILS proc,for ex.
Brgds
Alex