So I've now tried both ways (Note on a RUT955 not a RUTX09). The status command works for both methods. When sending mobileoff followed by mobileon, it just works. After pressing the 'do not click' button I found I needed to send a command to enable the interface, then follow it with the mobileon command. Something like:
password01 uci set network.mob1s1a1.disabled=0
password01 mobileon