Modification of CPLEX options for solving successive MIP problems‏

[Pratim]

Hello,

I have two MIP problems (MIP1 and MIP2) modeled with AMPL and I want to solve them with CPLEX with different CPLEX options.

The problem is that CPLEX keeps using the same options, i.e., those defined for the first MIP problem.
Here is the code that I am using.

problem MIP1;
option solver cplexamp;
option cplex_options ' bestnode';
solve MIP1;
problem MIP2;
option solver cplexamp;
option cplex_options ' bestnode uppercutoff=1345';
solve MIP2;

The additional CPLEX option ‘uppercutoff=1345’ is not taken into account by CPLEX. Indeed, CPLEX generates a number of integer solutions with objective value strictly larger than 1346.
Why is it?
How can I resolve this issue?

Best regards,
Pratim