Digital BW, The Print

Tom,
my experience is with a 1270 with spongeless - should be close enough
to make useful comment.  This has not been trouble free, though not as
 bad as your trouble.  

Given your inks are the same as you had before, and there is nothing
really to block in a spongeless cartridge (mine came with pull tabs
that must be removed, of course), I can't think of anything except air
leaks or air locks. 

After one refill I definitely had air leaks at the plugs, this led to
ink leaks (mixed good and bad nozzle checks and blobs of ink).  That
does not sound exactly what you have, but I wonder what a very small
leak would do.  I think the plugs need redesigned (there was no
damage visible but certainly there was a leak - tape fixed it).

The purpose of priming is to remove an airlock, with the black
cartridge and the outer "colours" it was quite easy to see when
sufficient ink was pulled out to remove the air bubble(s) around the
poppet valve and exit port.  This was not easy for the 3 inner inks on
the "colour" cartridge (no way to see in properly). 
In the end I just pulled a bit more than sufficed for the others (from
uncertain memory about 1 to 1.5 ml - sounds like more than you pulled).

To be on the safe side pull a bit more.  If you really fill to the max
there is plenty of ink beyond the limit set by the chip. I only primed
on the first fill as the ink remained continuous above and around the
valve.  

Ken