Furthermore, a good vendor would stand behind his product and replace it should it not meet the specifications.
If you really want tight matching, then you should speak to the vendor first, and if they can't guarantee what you need, go elsewhere. No one else will do your groundwork for you.
As others have already indicated, having individual bias adjustments eliminates most of concern, but whose who have experience with tubes also know the adjustment you made today will likely change in a few days.
I think you make a perfect case for expectations not meeting the reality.
