the puzzle of darker teak  

Photos would be very...
Photos would be very helpful.
There is teak that is quite dark brown with much less orange. I believe it is older teak that hasn't had much UV exposure throughout the years.
BUT, I bet that what you have is afrormosia. I have a Reenskaug/Bramin rocker in solid afrormosia, and I had a couple of Anderstrup generic dining chairs in afrormosia as well. A lot of scandinavian furniture used afrormosia here and there. Often drawer fronts with routed recessed pulls would be made of afrormosia with a teak veneer over top. I've seen small table tops made this way also. The Norwegians did this more than the Danes. And the English used a lot of afrormosia when they started making Danish-inspired pieces, which is why you see the two tone wood in them, lighter normal teak, and much darker brown afrormosia.
It is harder, heavier, and tightly grain, especially compared to teak.

This is what it looks like. ...
This is what it looks like. NOTE this is the lighter color when recently cut. It darkens with age.

And it darkens with age to...
And it darkens with age to the color of this end grain photo:

Here are some pictures. The...
Here are some pictures. The chairs that get more UV are definitely lighter and the lighter it gets, the better you see the grain. Looks like I will need to lets these pieces sunbathe. For this type of teak, it almost seems like BLO works better than teak oil. Maybe they don't even need oil, just a really good hand finish like rosewood.

That is afrormosia.
UV li...
That is afrormosia.
UV light will eventually bleach any wood.
"Teak oil" is usually for exterior teak and has UV blockers in it which is basically a sacrificial dark substance that get destroyed by the UV before it can get to the wood. So it can darken indoor furniture which gets little UV compared to the deck of a boat. Aside from that it is probably boiled linseed oil based.

I use scan-care teak oil,...
I use scan-care teak oil, but that is probably unnecessary for this specific type of teak. Do you know if afrormosia is oilier than the usual teak? I don't even use oil on my solid rosewood pieces as the natural oils come out when rubbed or heated up. Also, I have some system cado dressers that use afrormosia in the center part of the drawer as a nice color contrast to the teak veneer. Thanks again for the information.

Afrormosia is not a type of...
Afrormosia is not a type of Teak (Tectona Grandis). And it is not a notably oily/resinous wood.
It is sometimes called African Teak, (and has lots of other names too) not because it is a type of teak, but because it's durability outdoors makes it useful in the similar cases as teak. And it resembles teak a little bit.
http://www.wood-database.com/lumber-identification/hardwoods/afrormosia/

One thing though is that it s...
One thing though is that it says "Afrormosia has a distinct odor while being worked". I have sanded the bejeebus out of the wood and it really doesn't have an odor at all. Nothing like the strong odor that comes from rosewood or walnut.