Plated heat exchanger
Mcquay unit the line just past my txv go's into the top left of the exchanger and out the bottom right. My other circuit is vice verse going into that same heat exchanger. Now why not put lines inline top to bottom. With the unit off is hard to know the lines do that unless you backtrack the refrigerant lines coming out of your condenser coil.
It's easy to know since you know that they cross. I believe it's to increase heat transfer. Look how much tonnage you can get out of that barrel compared to equal tonnage of the other type.
are all plated exchangers set up this way?
Not all plate exchangers are set up that way. Often times the manufacturer will changed their standard piping arrangement for custom jobs such as small, packaged units.
The standard is usually accepted as top and bottom counterfed as you mentioned, but they can alter the piping arrangement if requested.