The geodetic VLBI technique is capable of measuring the Sun's gravity light deflection from distant radio sources around the whole sky. This light deflection is equivalent to the conventional gravitational delay used for reduction of geodetic VLBI data. Numerous tests based on a global set of VLBI data have shown that the parameter gamma of the post-Newtonian (PPN) approximation is equal to unity with precision of about 0.02 percent. However, the estimated accuracy is mostly dominated by the limited number observations near the Sun. I have processed 56 geodetic VLBI sessions between 1993 and 2005 when a reference radio source was observed within 5 degrees from the Sun (1662 single group delays in total) using different analysis strategies. The parameter gamma is still found to be close to unity with precision of 0.06 per cent, whereas subsets of VLBI data measured at short and long baselines produce some statistical inconsistency. In particular, at a shorter range of baseline length, the formal error is better (0.04 per cent) in spite of a less number of observations. This effect depending on baseline length may highlight some deficiency of the conventional VLBI group delay model, rather than a problem of the theory. Nonetheless, more observations near the Sun are important to improve the formal error of the PPN parameter gamma.