Custom security trimmer and result counts (11 results)

Sharepoint 2013 - we have a custom security trimmer, and it appears that the result counts on the first page are always 11, even though there may be thousands of results. Clicking "next page" advances this to 21 results, and so on.

Firstly - is this standard (and poor) behaviour for Sharepoint custom security trimmers, or is the trimmer in this case (as supplied by a vendor) badly written?

Preferential answers, in order, would be:

• How to fix this to provide better or more exact counts OR


• Confirmation that this is normal and expected behaviour (eg that all custom security trimmers will operate in the same manner), but that there is no way to obtain an accurate result count with a custom trimmer

Thanks for any feedback in advance. I'm hoping for a fix, but I'm not betting the farm on it.