Contextually optimizing each post for a single keyword is considered a best practice with WordMetrics. Because each primary search term can contain dozens of associated semantic index keywords, adding additional search terms, may result in adding potentially hundreds of related semantic terms per post. Depending on the length of your content, generating multiple semantic indices may result in unnatural sentences and readability issues.
Because there are already multiple relevant terms in each WordMetrics semantic index, well optimized pages generally perform well in more than one keyword. Articles optimized for a single keyword also generate traffic from other search contextually relevant terms.
If your use case requires optimization for more than one search phrase, it is recommended that you split longer articles into two or more parts and optimize each section independently.