Your LSAPI configurations are over tuned. Try the following
LSAPI maxconns=150, PHP_LSAPI_MAX_REQUESTS=2000, PHP_LSAPI_CHILDREN=150, persistConn=1, pcKeepAliveTimeout=N/A, backlog=100, instances=1
if the "WaitQ" for the lsphp external app in the real time status report is constantly non-zero...