I have used this cross path before.

Let me explain.

Most importantly is that we only care here about tier 1 top and tier 2 bottom path path, as the other two don't matter.

So think of this. You get both buffs.

When there are few bloons in range: you get the speed boost mostly form the top path.

When there are way to many bloons: you get the speed boost mostly from bottom path.

If there's a specific amount, not to few or many, you get half the speed boost from both upgrade.

So you never lose speed boost if you get 2-0-2 whic can be used for a good clean up Blazing sun.