But you can go and try doing it by torque limiter this way
Suppose your torque limiter has values for rpm till 5000 you got to set your value of injected amount the same for at least 4 values till the end in this case 5000 and in 5000 set it to 0
Then you alter rpm axes let's say you want cut on 4500 where it was 5000 you put 4510 (ten gap its interval of bangs ) and the previous value before where was 5000 set it to 4500
Try it maybe it will work I don't know because I don't have serious knowledge on that ECU