Transgo TF-2 question

i never understod the shiftcomand feature.. i didnt do it and i can still downshift at any rpm that i have wanted like shifting into first gear from 4500rpm in second gear and the gearbox have never ever let me down
im runing a 904 behind a pretty hot 340 and thrust that gearbox alot after puting the TF2 kit in it it makes for real nice snappy shifts ;)