I am new to this forum but I own a 7900 printer since february and keep having almost the same problems as you have. I am from Austria, Europe, so the problems seem to be independent from any factory - target market - or what ever issue.
My 7900 has ANC turned off and kept making cleanings almost randomly. Some days I could print without any troubles and on other days the printer made cleaning before every second printjob. I had talks to Epson Germany and there Austrian Support Company, no one had a clue, all told me to turn ANC off but it was turned off.
Then about four weeks ago I did a Firmwareupdate to 2793 (I hope I remember the number correctly) and the random cleanings dissappeared. I still had the described problems with manually cleanings of ink-pairs that cleans the whole had and wastes a lot of ink. So when today my Epson driver reported a new Firmwareupdate I didn't wait to install it.
Now version 2995 is active and my printer now makes a full cleaning before EVERY printjob. After updating I checked the menu, ANC was still off, made manuall nozzle prints, all clean and the sent the first printjob. The printer displayed "auto nozzle check please wait" then switched to "cleaning" and wasted 20ml ink. After the printjob (a small testprint that took 0.5ml ink), I sent another testprintjob (I was trying to get more contrast in the shadows of an image), again the printer displayed "cleaning" and again wasted ink before starting to print the job. After I adjusted my settings in photoshop according to the two testprints I started the real print, again with an unwanted cleaning.
I then called Epson support again, told them that a 5ml print had just cost me 40ml of ink for cleanings, again they didn't know anything about any problem concering cleanings, ANC or anything else. Currently Epson seems to be thinking about the problem, because the called me back twice to ask me which media brand I was using (of course Epson) or if I would let my printer be powered on all the time (which they do not recommend, but I'm not doing that anyway) and if I just had switched from PK to MK because then the printer is supposed to do a full cleaning (another thing that I just can't understand, that Epson again cleans the whole had insted of just the black ink heads) but I had not switched inks since a while.
Somehow it seems Epson (Europe) has no clue about these issues! Even though the printresults are excellent I sometimes think I'd better bought two Canon 6100 for the money of one Epson 7900 Spectroproofer. Summing up the last months I have amost spend $ 300 ink in unwanted cleaning, which makes me almost mad...
Has anybody else tried the new Firmware yet or had simmilar random cleaning problems?