So what happens when manganese is used to increase the error-rate?
Curiously, the Mutazyme PCR reaction fails if 1+ mM manganese chloride is added. It gives a faint band, not multi-banding. Mutazyme is simply a homologue of Pyrococcus furiosus polymerase that lacks the proof-reading domain. The dNTP concentration is the same as normal PCR and the primers only twice higher. The odd thing is that there is a secret stabilizing protein with it. So most likely this sensitive enzyme cannot cope with manganese.
This is not really the end of the world as the mutation rate hoped for is too high for epPCR (redundancy issues and frameshifts), while degenerate primer based strategies are more recommended, but it's a shame it does not stack.
*) 58% of nucleotide mutations are amino acid mutations if all mutations are equal. This is an empirically determined figure.