I don't understand the question asked, so if the OP could please elaborate a bit that would help.
If the question is about the direct correlation of performance plotted against price and the point where the performance curve begins to flatten against increased price, I stay away from that transition. I neither have the funds to spend in that region nor do I feel the need to waste valuable resources to gain such self-convincing, minor, improvements.
If the question is about the direct correlation of performance plotted against price and the point where the performance curve begins to flatten against increased price, I stay away from that transition. I neither have the funds to spend in that region nor do I feel the need to waste valuable resources to gain such self-convincing, minor, improvements.