What are Object Bounds first of all?

When I make certain mods, for example with my NVCE (NPC) mod, a lot of NPCs go through "Object Bounds" changes, in that they no longer are the same with the original FalloutNV.esm. What exactly does that mean, and is it okay to just leave them, or is it recommended to revert them back to what they were before?

I've never seen it be an issue, whatever the object bounds on a record are in the GECK ingame it just seems to use the appropriate ones from the skeleton or object nif.

What exactly are Object Bounds anyway?

Just the bounds of an object for pathing, as far as I can tell- that's separate from Havok. Creatures have a BSBoundNode (or something like that) in their skeleton for example which outlines their size, which can be tweaked to make say Securitrons able to fit through doorways.