Wow. That's really expensive though. 13 a cu ft is 351$ a yard!
I have messed with ligna peat. The peat alternative made from triple ground redwood bark. I really like it. usually less then 50$ a yard. Really good for making heavy compost based soil lighter. It's in the vermi fire i believe. Similar ph to peat. Some of my favorite soil mixes i have made have it. It's also in vermi and vermifire.
Bark is typically a filler and can be antimicrobial. Potting soil companies get it free or super cheap ($10-15 yard) from the timber industry. They then list it as "forest humus" or "composted bark fines" or some other good sounding name. It really does nothing beneficial in regards to plant growth and health. There's a reason we use it as a weed suppressing mulch in our ornamental landscapes.
I would suggest trying similar mixes without the bark and I bet you would get even better results.
And the cost is really the killer for me with the Pitt Moss. I love the concept, but it is so expensive and lacking the microbiology I get when I use peat.