Perhaps both made of mortar and used as one. Concave shape seems well suited to grinding things, which would support the obvious wear on its interior. Slightly overlying ashlar feature 7395 on one edge, suggesting either 7395 is much older than originally thought and all but the uppermost course is still buried and was also in antiquity, or 7395 was heavily spoliated in antiquity, to the point where a presumably ground-hugging feature like a mortar could cover it. 7384 seems like one of the later features in room H15. It is unclear whether it had more verticality lost either during SAR excavation, taphonomically, or in antiquity.