1. The Koran is the infallible word of the God, the Bible is an anthology explicitely compiled by priests and Bishops, leaving aside the OT the NT is NOT an actual source of absolute authority, because there is no "Book of Jesus" i.e. no direct word from God. It's an important point and it means that Christians can make judgements without actually going against their Holy text as a whole, that's not possible with the Koran because it is absolute. This is not to say that Christians have not claimed Biblical infallibility but it manifestly is not built into the text itself.
That doesn't make sense .
If the Koran is absolute and different judgements cannot be made on interpretation of the texts then why are there so many different flavours of Islam and why is it continuously being studied , interpreted and having differing judgements given out ?