^^^Well, remember how you kept thinking this program was too easy? Now, your are beginning to see the realitly of it.
A)Just pay attention to the NUMBERS. Do not discount how much strength you will be gaining from neural improvements alone. That doesn't mean there is NO muscle gain it's just that it's hard to notice if your body is experiencing muscle growth more or less evenly all over right now. You are focused on the small parts. But think about a roll of paper towels. If you were to add one sheet to a roll it would not appear any thicker. How many sheets does it take before you notice the difference in the roll?
But right now your body is learning to call on the muscle it has more effienctly. You have to realize that you body only makes the adpatations which are necessary. When more muscle growth is necessary (and we have to force that through progressive overload) you will see the difference.
B) If you are gaining too much fat then yes, you need to adjust your diet.
If you are progressing each workout or at least once a week then it is not blind, right? You said yourself that last time you weren't even adding weight to the bar. Now you are. Once you hit a wall you may be able to microload or just do a backoff to get going again...and then you can switch up to a more intermediate program. But I think what you REALLY need to do is let go of all the "mass" hype of the program and just focus on adding pounds to the movments. Getting stronger. Then later down the road you will be bigger and all the little details you are worried about will be much easier to even out.
The "results" you are looking for a STRENGTH gains. Let the mass come as it will as a side effect. This will all pay off big time in the future. Yes I know that people gain "50 pounds" or whatever on Rippetoe's SS but Rip advocates a gallon of milk a day, lol. 50 pounds of what?
The only way to be successful is to FOCUS on the things that count on this program. You divide your attention between tiny little muscular details and getting stronger and you'll divide your results. All that stuff I was saying before I can't stress enough...the way you think about things affects the attitude with which you approach it. If you continue to do what you said you will then you will do fine....
It may be that you have already come close to exhausting your ability to progress this way. If so, that is fine. Just progress as long as you can and then move one to another way. Don't sweat it.
It is natural for legs to grow faster than upper body, btw.