Technical Question Regarding Levels During Taper
 

I found a thread from 2015 in which someone explains an excel formula for calculating buprenorphine levels based on time of dose, half life, etc. The question I have is this: When calculating actual effective buprenorphine levels, mustn't we first multiply the dose by the approximate bioavailability of the particular formulation, first? For instance, the bioavailability of a Suboxone film is something like 30%-40%. Thus, are we not assuming incorrectly if we use the entire dose in the calculation?

I'm curious because I have successfully tapered my buprenorphine dose down to a dosage of 0.1125mg every 24 hours, and my withdrawal symptoms seem to be changing as I get lower and lower. I took a urine test this morning, with a positive threshold of 10ng/mL, and tested positive, so I still have enough in my system to show up on an at-home urine test, but my levels must be getting quite low by now. I want to figure out about how much actual buprenorphine I have in my system at any given moment, and chart how that has changed over time, so that I can accurately predict where I will be when I jump off in two weeks, and each day thereafter, until it's essentially gone from my system.

Thanks in advance for any help anyone might have for me!