Section 27(1) of the Principal Act is amended by the insertion of the following definitions:

"'contributory retirement benefit' means a member's ordinary retirement benefit multiplied by the member's reckonable service during which, under the rules of the scheme, he was required to pay contributions to the scheme and divided by the member's total reckonable service;

'contributory scheme' means a defined benefit scheme under the rules of which members are, or have been, required to pay contributions to the scheme;

'minimum contributory retirement benefit' means a contributory retirement benefit of at least the minimum value required under section 35A;

'ordinary retirement benefit' means long service benefit, excluding any such benefit which is secured by way of additional voluntary contributions or which represents a transfer of accrued rights from another scheme;".