About magnetic anisotropy calculation

[skythinker]

Hi, guys. I face some difficulties about the magnetic anisotropy calculation about Co hcp now. I carry out the process as below, but find the MAE is much smaller than the experiment value. Is there any mistake in my calculation method?

My process:
First:
optimize the hcp Co structure (in spin polarized method)
Then:
carry out one static calculation: K points is 19*19*19,
PREC = high
ISTART = 0
ICHARG = 2
ISYM = 0
VOSKOWN = 1 (PW91 is used)
ISPIN = 2
MAGMOM = 3 3
ISMEAR = -5
LORBIT = 11
EDIFF = 0.1E-05
And then, I get the CHGCAR and WAVECAR, and do further calculation according to the manual. I set the INCAR file:
PREC = high
ISTART = 1 (read from WAVECAR)
ICHARG = 11 (read from CHGCAR)
ISYM = 0
VOSKOWN = 1
ISPIN = 2
MAGMOM = 0 0 3 0 0 3
LORBMOM = .TRUE.
LNONCOLLINEAR= .TRUE.
LSORBIT = .TRUE.
SAXIS = 0 0 1 (magnetic direction)
NBANDS = 32 (twice in static calculation)
After that, I change the SAXIS to (1 0 0) and (0 1 0) to get three direction's total energy.
I find the difference between (001) and (100) total energy is in 10^(-6)eV order, but in former experiment and calculation, the result is 10^(-5)eV order.
Why there are so huge difference?
Is my calculation method correct?
Thank you in advance~

[support_vasp]

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