Epson Work Force WF 3640- OS X - two sided printing nightmare

[ralphiedee]

Been trying this all day and a already blew a tank of ink. How the heck do I do this? Here is EXACTLY what I do

From Photoshop select print
paper comes out fine with paper loaded in tray 1 and tray 2

then I take the printed paper and insert it in the back slot
I get message that printer is adjusting to print from back.
Then get message to either Eject paper or hit OK to send print job.

I hit Ok go back to Photoshop and select printer set up / Print settings
Make sure two sided options are selected, hit save and then print

Printer says paper ejecting then back loaded paper comes out and a paper from the 1st tray prints the doc on a new page.

Any help???????