HAProxy ignores nbproc

In our test environment we've identified a strange HAProxy behavior. We're using the standard RHEL 7 provided haproxy-1.5.18-8.el7.x86_64 RPM. According to our understanding, the total number of accepted parallel connections is defined as maxconn*nbproc from global section of the haproxy.cfg. However if we define: maxconn 5 nbproc 2 we'd expect total number of parallel connections to be 10. But we can't get over maxconn defined 5. Why is the nbproc being ignored? Here is the complete haproxy.cfg: # Global settings global log 127.0.0.1 local2 warning log 10.229.253.86 local2 warning chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 5 user haproxy group haproxy daemon nbproc 2 # turn on stats unix socket stats socket /var/lib/haproxy/stats stats socket /var/run/haproxy.sock mode 600 level admin stats socket /var/run/haproxy_hamonit.sock uid 2033 gid 2033 mode 600 level admin stats timeout 2m defaults mode tcp log global option tcplog option dontlognull option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 30s timeout server 30s timeout http-keep-alive 10s timeout check 10s bind-process all frontend ha01 bind 10.229.253.89:80 mode http option httplog option http-server-close option forwardfor except 127.0.0.0/8 default_backend ha01 backend ha01 balance roundrobin mode http option httplog option http-server-close option forwardfor except 127.0.0.0/8 server server1 10.230.11.252:4240 check server server2 10.230.11.252:4242 check listen stats 10.229.253.89:1936 mode http stats enable stats hide-version stats realm Haproxy\ Statistics stats uri / stats auth admin:foo