updating per-page on page > 1 position problems

[rococodogs]

I'm having trouble coming up with a title for this issue, so please feel to suggest a better one.

When changing the per page value on a set of search results, the new start index will be per page + old start index, which, when that value is greater than the total number of results, causes nothing to show up. We need to look for this excess and act accordingly to prevent it.

steps to replicate

1. get all search results
2. page through a few times (the gif uses 4)
3. change per page to max (250)