I did some poking around and here's what I'm seeing. I created a variable and named it state. The value is Ohio. And I created a second variable and named it City. Its value is Cleveland.
Here is the TOC innards:
I note that the lines holding the state variable show a 4. Which seems to coincide nicely with the number of letters in Ohio. And the City variable shows a 9, which, oddly coincides with the number of letters in Cleveland. So my guess for the varying numbers highlighted in the image above is that it's kind of a checksum or something to that effect to track how many characters the variable value contain.
As for the leading 0, I don't have any explanation quite yet.
Okay, I believe I've sussed out the meanings.
Take a look at the image below.
In this image the value of state is MO. As you can see on line 9, the word "Absentee" is listed. And if you add the space, that would consume nine characters. So we now have 9, 2. With the two indicating the number of characters the variable now contains.
Huh, such a simple answer. I have two sets of Single Source Layouts that I generate and my team mates were thinking the numbers had something to do with that and we never would've guessed that it's a simple count of the characters. Thank you very much for your help, Rick!!