57-year-old female with widely metastatic breast cancer and intractable pain on Oxycodone Extended Release 80 mg P.O. Q6H ATC with Oxy-IR 30 mg P.O. Q3H PRN (taking ATC). You determine the patient could benefit from rotation to methadone. Which is the most appropriate new regimen? (Hint: do not calculate for cross-sensitivity, as worsening pain accounts for this; use 10:1 morphine-to-methadone conversion.)