Strictly speaking, a Mother culture IS a concentrated source of bacteria. You put the breaks on by refrigerating at optimum concentration, just before it becomes too acidic and the bacteria start dying off. Just like yogurt.
I always adhere to the "If it ain't broke, don't fix it" philosophy. However... since you are under the 1.5% level you might want to try just a little more starter and see what happens. Jumping from 8 ounces to 10 ounces doesn't seem like much, but that would be a 25% increase in starter bacteria. There are several things that will do. These may be even more important and give more consistent results if you aren't using a pH meter.
1- Increase acidification rate substantially from the very beginning.
2- Given the same amount of ripening time, that will give a lower pH at rennet.
3- That will improve the efficiency of the rennet.
4- Should give a little better curd set.
5- Will give a better pH curve throughout the entire cheese make.
6- The entire make will happen a little faster.
7- This will NOT make your cheese drier or more acidic. Just watch your times and tactile clues a little more carefully.
8- The higher levels of bacteria will contribute to aging and proteolysis.
9- I don't do many soft or lactic cheeses, but I'll bet the higher 1.5% concentration will give better results on a lactic set.
You're doing great, so feel free to ignore.