Thanks but why Caesar gives me lower results than beam theory?

Exemple:
12inch pipe 10S
12 meters long
A312TP304L
ANC at one end and Vertical restrain + rotation locked at the other end
No pressure, no temperature, no insulation, empty pipe

Mid span deflection from caesar and beam theory formula = 1.75mm
But for stress: CAESAR = 12MPa // Beam theory = 18MPa