So my understanding of what this offers is:
If an object is stored within a planet's orbit, any platform in the same orbit can withdraw and install that object.
-Platforms take precedent
-Everything else has a delay.

Is that correct?

Your understanding is mostly correct, but slightly simplified.

If an item is in the orbit of a planet, platforms within the same orbit can supply ghost-required items to each other. However, this only applies to actual ghost requests and only if another platform in the same orbit has the required item available.

Platform foundations (space-platform-foundation) have strict top priority. They are delivered first, and if necessary, other item stacks may be removed from the hub to make room for them.

All other items are intentionally delivered with lower priority and in smaller batches to avoid congestion and instability.

Deliveries are orbit-only and happen with a short delay (simulated flight time).

That's phenomenal, I've added this to my load-order. I'm going to have a dedicated "construction yard" platform now.
I consider my playstyle a rather patient one, but less micromanagement is always a plus.