kt 88 shungyang treasures in mc275


I have recently installed the treasure kt 88 in my mc275.  I am noticing tube glare that was not there with my original tung Sol 6550 tubes.  They also seem to be a bit forward in presentation in comparison.  How long does it take these to break in?  Or, is this the sonic signature of these tubes?
tzh21y
I'm not trying to rock the boat as I have broken in many items (including tubes) but 400 hours for those tubes seems a little crazy. Do you think other tubes in your system may have become weaker which caused the KT88's to get soft?