The FMS VNAV path starts from 50" above the first brick of the runway and is only concerned per ARINC 424 to clear obstacles from there to the FAF. If there are no terrain or step down problems in the final segment then the angle will be 3 degrees. If there are obstacle factors in the final segment then the VNAV path will raised to clear them to a limit of 3.8 degrees "if I remember right from my FMS coding days". I.E. you are only guaranteed step down clearance inside the FAF. There is a new generation of approaches being tried out where the VNAV path will clear all step downs further out. I think you will have to activate approach mode or equivalent at a certain point.
A little light reading
https://www.faa.gov/documentLibrary/..._Circular/AC%2
090-105.pdfhttps://ieeexplore.ieee.org/abstract/document/5347485/?reload=true
ARINC 424 Navigational Data - Jeppesen