After just short of a year, I heard back from my request for classification of Orthrus from the Department of Commerce.
Their response reads, for the most part...
THIS ENCRYPTION ITEM IS AUTHORIZED FOR LICENSE EXCEPTION ENC UNDER SECTION 740.17(A) OF THE EAR AND IS DESCRIBED IN SECTION 740.17(B)(1).
In addition to that, they call it a 5A002.A item, which is more or less what I figured.
This page seems to say that as long as I have made a classification request, and that request has been answered that I am free to export (other than to places like North Korea or Iran) without any reporting requirements.