Digital BW, The Print

About a month ago I posted about getting a new MIS UT2 grayscale cart
(Epson 1280) that printed too light.  I have had no solution since 
then.  Forgive me for posting again, but I'd like to know if I'm the 
only one, or others have had the same issue in the meantime.

My story:  I made a good print with the old cart, then changed to the 
new cart. After two cleaning cycles, an imperfect nozzle check, 
another couple of cycles and a good nozzle check, I made a second 
print from the same file, in the same session of the same software.  

The new cart printed too light, and a little bluer than it should.  
It's like all tones from the middle up were boosted half a zone to a 
zone in brightness.  Highlights that had detail with the old cart are 
washed out and flat with the new one.  BO prints of the same file 
print correctly. I've since tried many files that I've made good 
prints of before--all print too light with the hextone inks, and 
correctly with BO.

I honestly don't think I changed anything in software or Windows.  I 
wasted hours, ink, and paper making sure I had not done something 
wrong inadvertently.  Yes, I've run nozzle checks.  Many.  Yes, I've 
checked all my software settings.  Yes, I've tried different Roarke 
tone curves in the set for 1280-UT2.  Same issue.  

I compared a PurgePattern6 printout to one from the old cart.  It 
appears that one of the light grey inks is a smidge lighter.

I wrote to MIS via their tech support web site.  No response for a 
week. I finally called.  They exchanged the problem cart for a new 
one. It had a lot number one greater than problem cart.  The new cart 
also printed too light. 

I wrote to MIS again.  Someone asked me to do some ink drawdowns for 
him, which I didn't really have the time or tools for.  Then work got 
busy, and the holiday weekend came up, and I haven't had time to deal 
with it further.  I also began to suspect that maybe I was being 
asked to jump through hoops in the hope that I'd give up and go away.

So, has anyone else had this problem with MIS greyscale inks 
recently?  I'm really upset. UT2 gave me a consistent, reliable 
working method for a couple of years, and now the rug has been pulled 
out from under me.

I believe one of the lighter grey inks is too light in both carts 
I've received recently.  Is MIS going to fix this issue and stand 
behind its products?  Or should I maybe be looking for another 
solution?  

--Peter