PMDG 747 QOTSII module version 1.5 programming problem

 I now want to increase the function of FUEL_CTRL_SWITCH. Just like Overhead-Engine control, you can control two engines at a time. This is what you wrote:
function OH_ENGINE_1and2_START_on ()

    OH_ENGINE_1_START_on ()
    _sleep(100,200)
    OH_ENGINE_2_START_on ()
end

function OH_ENGINE_1and2_START_off ()
    OH_ENGINE_1_START_off ()
    _sleep(100,200)
    OH_ENGINE_2_START_off ()
end

Similarly, I wrote the function value of FUEL_CTRL_SWITCH:

function ENG1_and2 FUEL_CTRL_SWITCH_run ()
    ipc.control(PMDGBaseVariable + 968, 0)
    DspShow ("ENG1", "run")
    DspShow ("ENG2", "run")
end

function ENG1_and2 FUEL_CTRL_SWITCH_cutoff ()
    ipc.control(PMDGBaseVariable + 968, 1)
    DspShow ("ENG1", "cut", "ENG1", "cutoff")
    DspShow ("ENG2", "cut", "ENG2", "cutoff")
end

function ENG1_and2 FUEL_CTRL_SWITCH_toggle ()
if _tl("switch_968_74X", 100) then
       ENG1_and2 FUEL_CTRL_SWITCH_run ()
else
       ENG1_and2 FUEL_CTRL_SWITCH_cutoff ()
end

But it didn’t work. What do you think is the problem? Please advise, thank you very much