Never been a fan on the 'per yard installed' pricing. We can maybe do this with a tree install job for example (per tree installed,) but never mulch.
No two mulch jobs are EVER the same. And then there's black, brown, cedar, pine straw, cyprus..... I would hate to use a blanket formula for mulch without truly figuring the labor required for each different job and it's challenges. I take into account all job logistics when figuring labor.
We always price
And when you have a 4 man crew on a mulch job all day, the "price per yard" doesn't mesh with labor/material pricing bundles.