Pellux I'm not sure you can use "true", try changing to "1" instead, at least that's from the tests I did.
This is my config on MW3 and it does just that. So it's either an issue with the "true" values or you didn't add/configure a manage dvar properly I guess
//////////////////////////////////////////////////
// BOT WARFARE //
//////////////////////////////////////////////////
set bots_main "1"
set bots_main_firstIsHost "0"
set bots_main_GUIDs ""
set bots_main_waitForHostTime "0"
set bots_main_menu "0"
set bots_main_debug "0"
set bots_main_kickBotsAtEnd "0"
set bots_main_chat "0"
set bots_manage_add "0"
set bots_manage_fill "4"
set bots_manage_fill_mode "0"
set bots_manage_fill_kick "1"
set bots_manage_fill_spec "1"
set bots_team "autoassign"
set bots_team_amount "0"
set bots_team_force "1"
set bots_team_mode "0"
set bots_skill "4"
set bots_loadout_reasonable "1"
set bots_loadout_allow_op "0"
set bots_loadout_rank "80"
set bots_loadout_prestige "0"
set bots_play_move "1"
set bots_play_knife "0"
set bots_play_fire "1"
set bots_play_nade "0"
set bots_play_take_carepackages "0"
set bots_play_obj "1"
set bots_play_camp "0"
set bots_play_jumpdrop "0"
set bots_play_target_other "0"
set bots_play_killstreak "0"
set bots_play_ads "1"
set bots_play_aim "1"
undefined