Problem with traffic generator

Using RB951G on V5.26
Trying to measure latency of Internet connection (from fiber connection w/provider 1 to LTE access w/provider 2)
Each internet access service has its own CPE

RB951 setup is as follows,

Ether1
Ether2 - connected to PC (Ether2 is master)
Ether3 - connected to LAN side of fiber connection CPE
Ether4 -
Ether5 - connected to LAN side of LTE CPE

With port mirroring in the RB951 and Wireshark, I can see the traffic generator actually sending packets to the fiber connection LAN and I can see those packets received by LTE CPE and forwarded into RB951-Ether5 (although destination MAC is that of Ether2), so routing and port forwarding in the receiving CPE are OK, but I don't get any statistics with the CLI or thru the web server page.

Config is as follows

[admin@MikroTik] /interface ethernet> print
Flags: X - disabled, R - running, S - slave

NAME MTU MAC-ADDRESS ARP MASTER-PORT SWITCH

0 ether1-gateway 1500 D4:CA:6D:DC:A7:DA enabled none switch1
1 R ether2-master-local 1500 D4:CA:6D:DC:A7:DB enabled none switch1
2 RS ether3-slave-local 1500 D4:CA:6D:DC:A7:DC enabled ether2-master-local switch1
3 S ether4-slave-local 1500 D4:CA:6D:DC:A7:DD enabled ether2-master-local switch1
4 RS ether5-slave-local 1500 D4:CA:6D:DC:A7:DE enabled ether2-master-local switch1

[admin@MikroTik] /ip> address print
Flags: X - disabled, I - invalid, D - dynamic

ADDRESS NETWORK INTERFACE

0 ;;; default configuration
192.168.88.1/24 192.168.88.0 wlan1
1 192.168.15.15/24 192.168.15.0 ether5-slave-local
2 192.168.1.210/24 192.168.1.0 ether3-slave-local
3 X 192.168.1.211/24 192.168.1.0 vlan3
4 X 192.168.15.16/24 192.168.15.0 vlan5

[admin@MikroTik] /tool traffic-generator> packet-template print
0 name="routing-1" header-stack=mac,ip,udp port=port1 mac-src=D4:CA:6D:DC:A7:DC/FF:FF:FF:FF:FF:FF assumed-mac-dst=FF:FF:FF:FF:FF:FF assumed-mac-protocol=ip
assumed-ip-dscp=0 assumed-ip-id=0 assumed-ip-frag-off=0 assumed-ip-ttl=64 ip-src=192.168.1.210/32 ip-dst=5.57.24.131/32 assumed-ip-protocol=udp
assumed-udp-src-port=100 assumed-udp-dst-port=200 ip-gateway=192.168.1.1 data=uninitialized data-byte=0

[admin@MikroTik] /tool traffic-generator> stream print
Flags: X - disabled, I - invalid

NAME DEFAULT-PORT PORT ID PACKET-SIZE MBPS PPS TX-TEMPLATE

0 str1 port1 port0 0 1450 3 0 routing-1

I have tried to follow the example in the wiki manual to no avail.

Only thing I have not been able to duplicate from that config is to assign "num=x" in stream definition.
The router would come back with an error if I tried to set a num value within the stream definition.

Can anyone help?

Thanks in advance,
Juan