I recently realized something about the shenanigans of published RPG articles, modules and supplements that throws off my various 3d6-in-order, etc. converters for Mutants and Death Ray Guns and Song of Blades and Heroes.
The characters in those RPG books were statted to be the class the writers wanted them to be for the story they were telling. None of those knights, witches, thieves and wizards were randomly rolled.
So to keep things honest I now do the following:
Immediately after converting a published character’s 3d6- or d%-in-order abilities to Song Of stats, degrade Quality and Combat by one each.*
Then apply Level advances to stats and special abilities.
*: No need to do this if you know for a fact the character was rolled randomly in order.