Epson 3880 VLM ink consumption

Hello everyone.
I recently outfitted an Epson 3880 with Piezography Pro inks.
I am finding that the VLM cartridge (Warm Tone Medium Grey) is being consumed far more than any other cart. It is empty while the others are 2/3rds full. All I have been printing is Clay Harmon’s B&W Torture test. The prints have been perfect.
Does this seem normal?
Thank you.

It’s normal