Are PhotoBLK and MatteBLK the same, swappable?

Open Discussion
1

My Piezo printing is currently on a 3880. I print almost exclusively to Han. PhotoRag 308 I have no plans to print to luster or glossy paper. But there are the two black ink positions. Are the inks different? I have to set the printer to use one or the other, QTR has a setting for which to use, also. Does it matter which? I would use up all Matte and only Photo from head cleans.

2

The matte black is for matte paper printing and the photo black is to be used for gloss paper printing.

best,
Walker