ABAQUS element stress values

Why are the element stress values obtained using the PYTHON code different from the element stress value obtained by querying directly in the CAE interface?
The code is as follows:
odb = session.openOdb('odbname', readOnly=False)
ele = odb.rootAssembly.instances['partname'].getElementFromLabel(label=elelabel)
step = odb.steps['Step-1']
last_frame = step.frames[-1]
fop = last_frame.fieldOutputs
fopS = fop['S']
ele = fopS.getSubset(region=ele).values[0]
x0 = ele.data[0]
x1 = ele.data[1]
x2 = ele.data[2]
x3 = ele.data[3]