Several things are wrong with this post. The exome is the protein coding portion of the genome. It does not change except by somatic mutation, same as the rest of the genome. Genotyping is the act of decoding variants in a genome and does not have anything to do with the underlying technology used. To my knowledge both ancestry and 23andme still rely on microarrays to do genotyping, though 23andme experimented with whole exome sequencing (which is not low coverage) in the past.