Greetings!
LocationCriterionService is one of those services that has a finite number of results that could possibly return, so the paging mechanism was not utilized since paging is meant for handling larger requests. If you pass it in, as you can see, there won't be a change in the results. If you take a look in our code examples (
https://developers.google.com/adwords/api/docs/guides/location-targeting#look_up_location_codes_for_a_region), paging is not used.
I do appreciate you being so observant to notice this. That behavior for this particular service has been around for a very long time, and the results coming back are limited, so we have kept the behavior as is. If we were to try to change it at this time, it may break someone else's code.
Cheers,
Nadine Wang, Google Ads API Team

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