You could be right. There is no mention of TENNs in the Akida 1 datasheet, but it is mentioned in the Akida 2 datasheet.
The MACs for Akida 1, and according to my hypothesis also for 1500, are 4*4, while the MACs for Akida 2 are 8*8.
So my question is, if the MAC support wasn't added to Akida 1 for TENNs,
I've just found the 1500 brochure and, as you say, there is no reference to TENNs, which is pretty conclusive:
View attachment 92836
View attachment 92837
I'll delete my earlier post as it is incorrect.