Hey stone! I'm glad you asked me to elaborate further. Although I did not mention Arimidex's ceiling effect in this thread I did in others. What I am getting at is exactly what you said.
Neither you nor I know for sure, but perhaps the OP will acquire 50% inhibition at a dosage of 0.5mg ED. If he runs it at double that dosage (1mg ED), not only does he not gain any beneficial effect of more aromatase substrate inhibition, but he also will affect his lipid profile more detrimentally than if he stick with the dose of 0.5mg ED.
Another thing to take into consideration is anastrazole's hepatic metabolism. If he is taking 1mg daily, then he is occupying way more cytochrome P450 oxidases than with a lower dose. This will undoubtedly alter the metabolism of many other substances and therefore also their serum protein binding levels, bioavailability, half-life, etc. Just think about if he were running an oral at the same time and the potential results. And as you know Stone, many OTC supplements are hepatically metabolized as well...