Getting all of the knobs to update instead of just some

Hey there,

I'm probably missing a simple step here but for knobs 3 & 4 they do change the sound but do not reflect the updated numbers when being moved. If I hit apply, the numbers do get updated. I've been looking through to see what I'm missing. If I change knobs 3 & 4 to the same slot as knobs 1 & 2 then they do update automatically.

What step am I missing?

on init
    make_perfview
    set_ui_height_px(500)
    set_ui_width_px(1000)

declare ui_knob $Knob_1 (0,1000000,1)
set_text($Knob_1,"Verb Wet")
move_control($Knob_1,1,4)
make_persistent($Knob_1)

set_knob_label($Knob_1, get_engine_par_disp($ENGINE_PAR_SEND_EFFECT_OUTPUT_GAIN,-1,0,0))
make_persistent($Knob_1)

declare ui_knob $Knob_2 (0,1000000,1)
set_text($Knob_2,"VerbTime")
move_control($Knob_2,1,7)
make_persistent($Knob_2)
set_knob_label($Knob_2, get_engine_par_disp($ENGINE_PAR_RV2_TIME,-1,0,0))
make_persistent($Knob_2)

declare ui_knob $Knob_3 (0,1000000,1)
set_text($Knob_3,"Dly Wet")
move_control($Knob_3,2,4)
make_persistent($Knob_3)
set_knob_label($Knob_3, get_engine_par_disp($ENGINE_PAR_SEND_EFFECT_OUTPUT_GAIN,-1,1,0))
make_persistent($Knob_3)

declare ui_knob $Knob_4 (0,1000000,1)
set_text($Knob_4,"Dly Time")
move_control($Knob_4,2,7)
set_knob_label($Knob_4, get_engine_par_disp($ENGINE_PAR_RDL_TIME,-1,1,0))
make_persistent($Knob_4)

end on

on ui_control ($Knob_1)
set_engine_par($ENGINE_PAR_SEND_EFFECT_OUTPUT_GAIN, $Knob_1,-1,0,0)

set_knob_label($Knob_1, get_engine_par_disp($ENGINE_PAR_SEND_EFFECT_OUTPUT_GAIN,-1,0,0))

end on

on ui_control ($Knob_2)
set_engine_par($ENGINE_PAR_RV2_TIME, $Knob_2,-1,0,0)

set_knob_label($Knob_2, get_engine_par_disp($ENGINE_PAR_RV2_TIME,-1,0,0))

end on

on ui_control ($Knob_3)
set_engine_par($ENGINE_PAR_SEND_EFFECT_OUTPUT_GAIN, $Knob_3,-1,1,0)

end on

on ui_control ($Knob_4)
set_engine_par($ENGINE_PAR_RDL_TIME, $Knob_4,-1,1,0)

end on