Can I apply my adhesive directly to my porcelain tile rather than to the plywood subfloor?
You can, but applying the adhesive to the subfloor will give you a more level finish.
just makes the job slower..thats all...
You CAN ... but it's best to follow the directions and apply it to the floor.
That's not the way it is done, why would you prefer to do it backwards?
Throw the tile around like frisbees till they go in place. I'm a tiler. I would know.
Applying the adhesive to the tiles will be pretty messy.
It's called buttering. In some cases you have to. But on an open floor it much quicker to apply it to subfloor. Buttering also makes it a little harder to keep floor smooth and level