Sec.152(6)(a)(ii) meaning

Meaning in short........ If any other law prevails for such situation, then that law/act/rule will override....

Otherwise...... whatever stated herein will prevail/ be followed.

It simply means that in Public company ,there is a provision in the act for mandatory retirement of directors ( Which are not fixed term - MD,Nominee, Independent,Non Executive are fixed term ) so other than them other directors will retire everytime and are eligible for reappointment...If AOA don't have any provision ,then 2/3 are liable for Retire and 1/3 will retire every year ,consider this example

Suppose A Ltd has strength of 6directors ,
Mr.A - Chairman Executive
Mr.B - Executive Director
Mrs.C - Executive Director
Other 3- I/D

Now Mr.A&B and Mrs.C is only counted and 2/3 of 3 is 2 and out that 1/3 which is 1(Fraction will be next no),So one who is longest in tenure will liable to retire by rotation at every AGM