Service of notice and copy of certificate.

When a certificate has been filed under section 4 or transmitted under section 5 the Collector in whose office it has been so filed or to whose office it has been so transmitted shall cause to be served upon the defaulter in the prescribed manner a notice in the prescribed form along with a copy of the certificate: Provided that, where the Collector in whose office the certificate has been filed under section 4 has served a notice under this section, it shall not be necessary for the Collector to whose office it may be transmitted under section 5 to serve a like notice again.