duplex printing issue

[mdfurqan2012]

Dear All,
I have one Pro1357ex with postscript and one Pro8120s with Fiery Controller EB32.
I have to sent multiple MS word and PDF files directly drop in printer queue some files have only one page some have 2 or more pages. we have to print all files having more than one pages in duplex for that by default I set duplex open to left. it works perfectly on pro 1357 only files more one pages becomes duplex all other print in simplex and for simplex machine counts single page.
I do same setting for pro 8120s but when we drop files in queue of pro 8120s it prints single page in duplex means document prints only one side but paper runs through duplex unit and our machine counter counts 2 pages by that machine speed slow down due to duplex printing and machine counter and pages count by soft copy becomes different.
so kindly guide me to resolve that issue.

Thanks in advance

[Blizzoo]

I experienced once a weird similar duplex printing issue, docs sent as duplex will exit single sided every time after many ways of fault finding on that PC, the machine was a B/W small office networked with 5 PC's and just one PC having this problem. Changing the network port from RAW to LPR in the print driver properties has solved the duplex issue.

You have a Firey attached to the problematic machine and the above may not apply in your case.