^ Actually with Chronic administration it can reach 50%, albeit probably in larger doses ; stilk it should average 30-40%
OP, just cut your tablet in half for a couple days, so 15mg SR, basically like 5-7.5mg 2-3x per day
Then take a quarter of a tablet, a mere 7.5mg, you will literally be on the equivalent of ~5mg oxy, or 2.5mg IV/IM morphine, which would be like 1/8th of a mg of buprenorphine (Zubsolve or liquid solution)
A couple more days, and you can quit - Suboxone really is overboard, just to get of of 30mg of morphine, SR once per day - trust me, unless you have pain and just want to experiment with powerful, long lasting and idiosyncratic partial Mu agonist
That small dose can be simply tapered after a couple of months of using - the above method is simple and should work.
Note that you can check comfort meds, though doubt they will really be needed, except some kind of analgesic perhaps - Good Luck