Retroarch.cfg question

I'm using 2 Xbox 360 controllers with RetroPie/ES, everything is working great. However, one annoyance is that with NES, B and A feel backwards. I want my thumb to rest across X and A on the XBOX controller. I thought this could be achieved by simply switching A and B in the NES retroarch.cfg file, which currently looks like below. (I swapped input_a_btn = “0” input_b_btn = “1”) Besides the fact that I left out my hotkeys, why isn't this changing the mapping?

Thanks,

# Settings made here will only override settings in the global retroarch.cfg if placed$

input_remapping_directory = /opt/retropie/configs/nes/

input_device = "Xbox 360 Wireless Receiver (XBOX)"

input_driver = "udev"

input_r_y_plus_axis = "+4"

input_l3_btn = "9"

input_r_x_minus_axis = "-3"

input_l_btn = "4"

input_load_state_btn = "4"

input_start_btn = "7"

input_exit_emulator_btn = "7"

input_l_y_minus_axis = "-1"

input_up_btn = "13"

input_r_y_minus_axis = "-4"

input_a_btn = “0”

input_b_btn = “1”

input_reset_btn = "0"

input_down_btn = "14"

input_l_x_plus_axis = "+0"

input_l_y_plus_axis = "+1"

input_r_btn = "5"

input_save_state_btn = "5"

input_r2_axis = "+5"

input_r3_btn = "10"

input_right_btn = "12"

input_state_slot_increase_btn = "12"

input_x_btn = "3"

input_menu_toggle_btn = "3"

input_select_btn = "6"

input_enable_hotkey_btn = "6"

input_l_x_minus_axis = "-0"

input_y_btn = "2"

input_left_btn = "11"

input_state_slot_decrease_btn = "11"

input_r_x_plus_axis = "+3"

input_l2_axis = "+2"

#include "/opt/retropie/configs/all/retroarch.cfg"