The probelm was that the antronix-Products-ResAmps-results.php page was including the splitterResults.php page as a plugin:
if("" == ""){
$WA_splitterResults_1408132175477 = new WA_Include("filters/splitterResults.php");
require($WA_splitterResults_1408132175477->BaseName);
$WA_splitterResults_1408132175477->Initialize(true);
}
I updated that to use the residentialAmplifiersResults.php page instead.
if("" == ""){
$WA_splitterResults_1408132175477 = new WA_Include("filters/residentialAmplifiersResults.php");
require($WA_splitterResults_1408132175477->BaseName);
$WA_splitterResults_1408132175477->Initialize(true);
}