In order to preserve biological information, it is essential that the sequence of bases in each copy are precisely complementary to the sequence of bases in the template strand.
Nucleotide excision repair proteins are mobilized to this area where one likely outcome is the expansion of nucleotides in the template strand while the other is the absence of nucleotides.
Because of the toroidal shape of the assembled multimer, the clamp can not dissociate from the template strand without also dissociating into monomers.