NDL versus PADI Tables

If you change your Conservatism setting in your watch, you also change the NDL time. Page 5 of the manual  "Conservatism: Sets the level of conservatism for decompression calculations. Higher conservatism provides a shorter bottom time and a longer ascent time. The Custom option allows you to set a custom gradient factor. NOTE: Make sure you understand gradient factors before entering a custom level of conservatism" 

A GF high of 95 should get you fairly close to PADI tables.

I think one should also note, that with the tables, the bottom time starts immediately. I think the computer tells you how long can you be at that depth, so those are in my understanding not directly related as one takes note of the time to descent and one doesn't. Of course then in reality people's descent rates differ and with tables your NDL stays the same, even you in the end are just 1 minute at the max depth as with computers things are totally different.

It's weird because I have chosen all of the three Conservative settings (low/med/high) and the NDL doesn't change.  Is there something else that affects the NDL?  I understand the difference between NDL and actual dive profiles.  All I want to do is to understand the mechanism behind how the Descent calculates the NDL, and calculates it about 5 mins less than the tables.  I have a Suunto Vyper Novo that shows 17 mins for 30m and my understanding was that Suunto were notoriously more Conservative than Garmin.

How exactly did you do the changes?  I cannot replicate what you said.  When I change either GF high, or chose standard conservatism factors I immediately get different NDLs.  This is what I did:

Go to Plan Dive, Compute NDL, Diving Now, select 32% and 30 meters.  It will then show the NDL.

Next I hold the button on the middle left to get to settings.  I go to dive set-up, conservatism (or directly the High GF), and change it.  Then click bottom right twice to end up on the NDL screen.  And it will show an updated NDL.