What's the difference between liquid methadone for withdrawel & pill form for pain management?

Also what would be the correct dosage when switching from 60mg oxycontin to methadone. The docs put me on 30mg & that was ok for about the first month. I'm thinking either 60 which would be 2 three times a day or 40 one four times a day.

: http://alcoholdrugstreatment.info/whats-the-difference-between-liquid-methadone-for-withdrawel-pill-form-for-pain-management