Toward vs. Towards

Web search results display blogversations which indicate that with the 's' is the British way, and without it, the American way. I don't know for sure, but personally, I don't think that gets to the bottom of it. 

I think (or like to pretend at least) that it's finer than that.
(I need help from experienced, language professionals, on this issue.)

These words, man...they are some volatile, dangerous stuff.

If you ask me, I think we should be using the 's' when the word being modified is plural, and drop it when it's singular. 

Case in point:

You wouldn't say "a thousand arrows rained down toward me" unless you specifically meant to point out that they were all launched at the same time. Thus raining down all at once, in one fell swoop. That would indicate a singular mass of arrows--falling toward me.

Another example. Take the rain (for instance):

"A million rain drops fell toward me" vs. "a million rain drops fell towards me."

The former would indicate the rainfall as a frozen moment in time: you know how, if you stare out at the rain, you can slow down and even momentarily freeze sections of falling raindrops, as your eyes glance downward at matching rates of speed? It's sort of like that, when using the singular, without the 's'.  But if you wanted to indicate the continuing or rather, constant fall of rain drops, you would use the plural form, with the 's': "A million rain drops fell down from the sky towards me."

A couple more examples, to rest my case: 

"What looked like three street thugs working together began ambling over towards me."
vs.
"The police officer walked directly toward me."

Look, I realize what I'm pointing out here probably isn't even a thing. I am just working toward understanding towards.  Any help would be vastly appreciated. . .