Whenever I put in a 410-a system, I use a TXV. I use 14 seer Goodman equipment as my standard. Every once and a while people ask to shave a couple bucks so I tell them I can drop it to 13 seer. My rep says I can just use the piston, but prefer the TXV for the ease of knowing to do the superheat and sub cooling to what it is. My question is, is this ok and is there any positive/negative to this practice. Any input would be nice, thanks.