Interstate state supply

Dear All,

Need clarification I am little bit confused w.r.t compulsory registration for export of services, as per notification https://cbec-gst.gov.in/pdf/integrated-tax/10_2017_IT.pdf interstate supply of service is exempt up to 20/10 lakhs. But as per opinion of senior speaker at seminar he is saying , export of service needs registration from day one.

Please clarify whether registration is must or not?