I think
@musicman nailed it.
Balkan blends are usually fuller English blends with oriental-forward proportions, where as Orientals are usually lighter pure Virginia or Va/Per blends with noticeable proportions of oriental leaves to flavor.
I am personally a huge fan of both: I find when used corrected it adds a sour, creamy taste to an heavier English or lighter Virginia and/or Va/Per blend. I used to love the way they worked with McClelland's way of processing Virginias but the alternatives now are great too.
I think it's L J Peretti that has a Lat/Or, it does NOT taste like Shortcut to Mushrooms but in many ways it reminds me of it, that's an excellent blend but I would hesitate to call it an Oriental but it does scratch the same itch.