Don't know if this is already discovered, but Shift + Alt = a strange display of information about the tile being hovered over.

Maybe this will help by providing some needed feedback?

Here's the info provided, and format

Level is the level above ground (0 = ground level) - floors built on a foundation are considered level 1.
The numbers next to "Room" *might* be related to environment scores - I noticed I seemed to get larger numbers (for the most part) in rooms with better light sources and paintings.
Vertex and Tile # are pretty closely related - obviously vertex is the closest point, while tile is the actual tile being reported.
Tile quadrant seems rather silly to me, but maybe there's a significance I haven't figured out yet. In any case, I *think* North is treated as the flat side 45 degrees left of the direction the daylight originates. The quadrants are in an X pattern on the tile, rather than a + pattern.
Num Objects on ground is not consistent that I can tell. Sometimes it appears to count 2 items, sometimes only 1. Weird.
Floor pattern I think corresponds to a guid, but I haven't figured out what surface type or locked mean. Every surface type I've found is "-1" and I have yet to find a tile that was "locked"

Again, I hope this helps!
[ Edited ]

Quadrants are probably for handling diagonal walls. When you've got a diagonal wall across a square tile, you can set different floors on either side.

Num objects probably counts all the objects on the tile, meaning even objects you can't see like social interaction objects and various types of markers, triggers, emitters, etc.

That makes sense about quadrants relating to diagonal walls.
As for Num Objects, I've had the thing count "1" when there was nothing but floor! I can't find the consistency there.

I hovered the thing over a tile with a couple sims and a social interaction and it told me there were 4 objects, so it seem the most likely explanation.

The floor is probably an object as well. It'd be the easiest way to account for them.