NRD at age 65, full benefits for term vested at SSRA, reduced at 65

[Gary]

A plan provides that NRD is 65 and 5 yrs participation.

It also provides that if you retire at age 65 you get your full pension.

However, if you terminate prior to age 65, then you can get your full pension at your SSRA. That is you would receive a reduced pension at age 65.

Has anyone seen anything like this and does anyone know where in IRC that such a provision is allowed?

thank you, gary