Lots of folks put a "d" in Roger, no prob there.
As to your question. I am disappointed that most tube "matchers" give numbers with no units. What are these numbers and under what conditions are they measured? If you ask a tube vendor if his tubes are matched of course he is going to say "yes" and in my experience little else. When I am in a fiesty mood and someone asks if my tubes are matched I reply "well what would you like them matched for?" That is usually followed by a long pause on the other end of the line. If I am in are very feisty mood I'll ask if he would like them to be the same size, color or some other silly thing which is about as silly as some tube vendor marking his tubes 76/76, 72/73 etc.
I determined in the RM-9 design that a direct coupled driver would improve bass attack and stability to a great degree. To my knowledge there were, and still are, no other direct (DC) coupled 2 stage drivers out there. In order to DC couple the two driver tubes the first tube must be well balanced for plate voltage because the second tube will amplify that difference to a point where the driver will distort prematurely. To make this work I came up with a simple, built-in system to allow the user to balance the driver by a simple LED indicated null. The input tube must have an inherent balance within 3 volts plate to plate at the operating plate voltage and current. We provide these balanced tubes at a very reasonable additional cost of $10 over similar tubes of the same grade. We have supplied phono tubes to Balanced Audio Technology with similar plate matching based on their operating conditions. From these examples one can see that "matching" is not a simple task, that it varies with the application, and that tubes "matched" in a Hickok tester are not likely to be matched in the person's unit.
For most applications it is tube gain that needs to be matched so that your left and right channels will be of equal gain and place the image in the center as it should be. This is of particular importance in preamps with no balance control. Depending on the preamp's tube configuration one might want to match the sections of the tube for gain or, in some cases, two tubes used in cascade should have the sum of the section gains equal. This is tricky stuff so don't be discouraged if this is TMI (too much information). This is a subject dear to me and I will expound on it if there is interest. For now I would like to make a very simple point. In the application of most dual triodes (12AX7, 12AU7, 6DJ8, 6922, etc) it is the voltage gain (mu) that is important, not the transconductance (gm). It is unfortunate that the tests our competitors make are usually (Hickok) transconductance tests. There is no guarantee that a tube with matched gm will have matched mu. In fact, it generally won't. This is why I designed our tester to measure mu directly and carefully chose plate current and voltages that these tubes normally see in circuit.
For power tubes the tests are entirely different, but thats a subject for another day.
