Create Service Binding creates entry in table=0 with a service-priority+1. Is this the expected behaviour?

Version: Boron SR1

Steps to reproduce the issue:

1) Create Service Binding (POST http://localhost:8181/restconf/config/interface-service-bindings:service-bindings/)

{
"services-info": [
{
"interface-name": "tun999a999a9a9",
"service-mode" : "service-mode-ingress",
"bound-services": [
{
"service-name": "ELAN",
"service-type": "interface-service-bindings:service-type-flow-based",
"service-priority": 5,
"flow-priority":10,
"flow-cookie": 134479800,
"instruction": [
{
"order": 1,
"go-to-table":

}
]
}
]
}
]
}

2) Check a new entry is populated in table=0 as follows:

cookie=0x803ffb8, duration=10.943s, table=0, n_packets=0, n_bytes=0, priority=10,in_port=1 actions=write_metadata:0xc000090000000000/0xffffff0000000001,goto_table:50

To have Service Index = 6 (110) in write_metadata actions, "service-priority" should be equal to "5" in json (= target SI - 1).