Typically that feature is used to find a recent post of someone's, increasing the number of results increases the amount of resources the usage consumes. People have tens of thousands of posts, that feature really isn't meant to be a way to look through all the historical posts of a person.
If you are looking for a specific post from someone you can use the full search feature and filter by the poster and it'll search all their posts.
Uncertainty is an uncomfortable position.
But certainty is an absurd one.