After you have segmented your users into different cohorts, you can decide to sample each cohort at a different rate. For example, if your users fall into 3 different pricing plans: "Enterprise", "Pro", or "Free." Because the "Free" plan has many more users than the other two plans, you might want to dial down its sampling eligiblity percentage to 5% and keep other two groups at 30%. This will mean that fewer users on the "Free" plan will be eligible to see a survey than the other two plans.
Acheiving this will require setting a dynamic sampling requirement in the code (rather than in the user settings UI). The variable that controls survey sample size is called wootric_registered_percentage and here's how this would look in our snippet (attached). You could then swap out the 33 and make this a dynamic field that responds to your user plan condition.
It is important to note that any future changes to sampling would have to be done to the code directly. Anything hard coded in the snippet overrides settings in the user interface.