Why only heterogeneous SNVs for validation using genotyping arrays?
The purpose of validating is to find genuine SNPs and not those caused by sequencing or amplification errors. It is extremely unlikely you will have a false homozygous SNP as a result of error. Just think about it. The same error, at the same base, occuring 80%+ of the time? Its not going to happen unless you have low coverage, and these SNPs should be thrown out anyway. You may have some cases where a genuine heterozygous SNP is called as a homozygous SNP. But that isnt much of a problem. It is still a genuine SNP. It would only be a problem if you were only interested in homozygous SNPs, in which case you will just need to validate everything biochemically, which you will need to do anyways.