LinkedIn returns at most 1,000 results for any single search, so a country-wide query cannot go deeper however many jobs exist. Turn this on and a country location becomes one search per major city, which is the only way past that ceiling. City searches return genuinely different jobs, not the same ones relabelled: measured on 'registered nurse', a 500-job United States walk shared just 3% of what New York, Houston and Phoenix returned, and those cities shared nothing with each other. Every city is a separate search and results are billed per item, so raise Max Results to cover cities x Max Results Per Search or the run stops part way. Locations that are not a supported country are left alone.