We present new z- and H-band photometry and proper motion measurements for the five candidate very-low-mass T-type objects we recently proposed to be members of the nearest OB association with the Sun, Upper Scorpius (USco). These new data fail to corroborate our prior conclusions regarding their spectral types and affiliation with the USco population. We conclude that we may be in presence of a turnover in the mass function of USco taking place below 10-4 MJup, depending on the age assigned to USco and the models used.