Regarding the "Which standard?" question, I think I answered that. I believe there is indeed one standard, held by God, outside of myself and objective in that anything I do or say can be measured against it. It is an immutable standard, and there are definite right or wrong answers. The only thing is that I realize I must attempt to interpret the best I can, and act the best I can, which due to my nature as human means I WILL err and I WILL interpret incorrectly.
If this divine moral blueprint needs to be interpreted, it is useless. You will interpret it through your own moral filter. Faced with a vague, self-contradictory text, what else can you do? In the end, you decide your own morality - just like the rest of us.
The problem lies, rather, in human nature...given that we are of finite mind and subject to error, most anything we engage in excepting hard mathematics (as opposed to statistics, especially statistics on human nature) will require interpretation...and in my belief, prayer and meditation. Again, though, this is why humility is so important, because we do not simply attain a state of perfection because we say we are Christian--we're always growing and have to be ready to accept correction in the process of learning.