Back Stress in Abaqus

Could you please advise if that is correct to select higher number of back stresses (as input) while simulating test results in Abaqus?

It appears to me that the higher number of back stresses (say selecting number of back stresseses in Abaqus >= 5) give me a better fit to the test results. For my case, 5 is an optimal value as increasing it will not affect the results, much.

Thank you.