SIMBAD query returns wrong (?) values for magnitude errors

Question

I'm using astroquery to simbad.query_region and obtain the magnitudes of the Stars in the region in certain bands (B,V,R).

simbad.add_votable_fields("flux(B)","flux(V)","flux(R)","flux_error(b)","flux_error(v)","flux_error(r)", "otype","sptype")
result_table = simbad.query_region(target_coords, radius='0.3 degree')

The code supposedly works, and returns:

     MAIN_ID      FLUX_B FLUX_ERROR_b FLUX_V FLUX_ERROR_v FLUX_R FLUX_ERROR_r
                  mag                 mag                 mag               
---------------- ------ ------------ ------ ------------ ------ ------------
UCAC4 440-052370 15.632           -- 14.717           -- 14.604        0.020
  TYC 4914-582-1  12.87           --  12.41           --    0.0           --
UCAC4 440-052382 14.137           -- 13.194           --  13.04        0.030
  TYC 4914-131-1 12.178           -- 11.708           --    0.0        0.035
UCAC4 440-052358 17.381           -- 16.407           -- 16.041           --
UCAC4 440-052354 16.976           -- 16.066           -- 15.743        0.090
UCAC4 439-051968 16.679           -- 15.727           --  15.36        0.080  

my problem is that while the magnitude values agree with those found in a in-browser query of simbad, for most sources the error values are not returned, and when they are they do not agree with what i find if i look up that MAIN_ID in browser. Am i searching the wrong fields?

I have not found any other plausible keyword and if those were wrong astroquery would return an error.