The ACS758 data sheet claims that the sensor is factory calibrated, and its output sensitivity is fixed for the fixed amount of current passing through the hot circuit. For ACS712, the output sensitivity varies sensor to sensor as per its data sheet which says that the sensitivity is 66mV - 185mV/1A current in the hot circuit. For sure, use of ACS758 is the right choice! The Selection Guide is taken from data sheet and is pasted below for quick reference.