why make mother culture? how to adjust for small batches?

[meyerandray]

I have only been able to find DVS culture in 50 liter packets, and I don't have a scale that weighs grams yet, so I have been dividing them in 5 approximately equal piles and storing them that way. Well recently I made a 3 liter batch, so I eyeballed approximately 1/3 of my approximately 10 liter dose of culture. With this highly scientific method, aren't you shocked when I tell you that my curd the second time around with the same recipe is different?
I have seen that many of you use measuring spoons, but I haven't quite gotten it- meaning that 1/4 tsp would be more than my approximate dose for 10 liters. I see that others use mother culture, would that help me? Or would it just further complicate my life?