No problem. Ok, makes sense now.
Well, I wouldn't really bother doing that. When the time comes and you're seeing such a physician, the dosage adjustment isn't going to be on a wide scale. Some will have a limit that they'll work up to, along the way, having you report subjective feelings/observations. Some will have a set dosage irrespective of where you're at, provided that you're generally below the high-normal range.
While I can see your point, this is not the way things will be done. Even if you had a lab value with you, it doesn't really mean much unless you get your future blood levels checked by the same exact lab. Even then, I doubt the physician, even the most progressive is going to take the time to find the exact dosage to get your testosterone levels at such an exact, previous level. Getting in a general range is the more reasonable approach and again, subjectivity comes in to play as well.
I wouldn't worry about having to show your testosterone levels to a physician in 20 years. Either you'll need to be hypogonadal, or if you're not, you'll likely be seeing a more liberal physician, in which case he/she will likely already have a set protocol which they follow, again, trying to get you in to the high-normal range.
Hope this helps.