Dear Sachin,
For determining applicability of the Act to a person employed, only his gross monthly salary should be taken into account. When the gross monthly salary exceeds Rs. 21000/= he automatically goes out of the ambit of the definition of employee for the purpose of payment of bonus under the PBA, 1965. The break up of " salary or wage " so defined under the Act is to be undertaken for the purpose of calculation of bonus only and not for applicability of the Act as a whole.
Can you please read section 12 of the Act once again more carefully? It only says that when the salary or wage exceeds Rs.7000/=, it has to be treated as Rs. 7000/= or the statutory minimum wages whichever is higher.