Ah yes, the top is how I'd usually do them.
You can select an edge and do 'extrude edges' but have no extrusion, but it'll extrude edge support loops... rather than the 'classical' chamfer which does the bottom one.
But the top one is technically no more accurate, just the normals are nicer because of the support loops.
In theory you can make the bottom one look more like the top one by using face weighted normals, or setting normals explicitly.
If you check out the polycount forums, and more specifically the wiki here:
http://wiki.polycount.com/wiki/Face_weighted_normals
It discusses some approaches to managing the normals.
I use the script here:
http://wiki.polycount.com/wiki/VertexNormal#SetNormals_MAXScript
"GetVertNormalsFromFace MAXScript"
You just select bunches of faces that you want to have normals 'conventionally' calculated across, and then run the script, which runs face weighted normal calcs over them
.
So for instance you'd select the forward faces of the actual bodywork and press the button, then you'd select the faces that are perpendicular to them (beyond the chamfer) and press the button.
This leaves the normals all either facing outwards of the body panel, or perpendicular to it... the chamfered edge then gets a blend of normals from out, to perpendicular (as per the diagrams on the wiki pages linked above)
That is technically more accurate of the actual topology, looks just as good as the method you've now chosen, AND it saves triangles too.
Just be cautious with using modifiers like edit mesh or symmetry above edited normals because they can be lost in some cases!
I'll be honest I used your 'new' method in the past because it works ok and looks ok and that's great.
I'm just letting you know that this method works nicely too, and in theory offers many advantages in areas like UV unwrapping, lower tri and vert counts, etc.
Keep up the amazing work though
99% of any project is making the main mesh. These are details and are just thinks to pontificate about later... don't worry about them too much