Use field symbols?

Hello Experts,

1) Can we introduce field symbols for this piece of code.

-

if ls_data_package-/bic/Z_amount1 ne 0.

ld_n_per = ls_data_package-/BIC/Z_date+0(2).

CASE ld_n_per.

WHEN 1.

ls_data_package-/bic/ZJ_amount1 =

ls_data_package-/bic/ZJ_amount1 +

ls_data_package-/bic/ZJ_amt1.

WHEN 2.

ls_data_package-/bic/ZJ_amount1 =

ls_data_package-/bic/ZJ_amount1 +

ls_data_package-/bic/ZJ_amt1 +

ls_data_package-/bic/ZJ_amt2.

endcase.

endif.

-

2) How much performance increase can be expected using field symbols.

Thanks very much for all your suggestions.

BWer