  We present the results of a long term orbit monitoring program, using sparse
aperture masking observations taken with NIRC2 on the Keck-II telescope, of
seven G to M-type members of the Upper Scorpius subgroup of the Sco-Cen OB
association. We present astrometry and derived orbital elements of the binary
systems we have monitored, and also determine the age, component masses,
distance and reddening for each system using the orbital solutions and
multi-band photometry, including Hubble Space Telescope photometry, and a
Bayesian fitting procedure. We find that the models can be forced into
agreement with any individual system by assuming an age, but that age is not
consistent across the mass range of our sample. The G-type binary systems in
our sample have model ages of ~11.5 Myr, which is consistent with the latest
age estimates for Upper Scorpius, while the M-type binary systems have
significantly younger model ages of ~7 Myr. Based on our fits, this age
discrepancy in the models corresponds to a luminosity under-prediction of
0.8-0.15 dex, or equivalently an effective temperature over-prediction of
100-300 K for M-type stars at a given premain-sequence age. We also find that
the M-type binary system RXJ 1550.0-2312 has an age (~16 Myr) and distance (~90
pc) indicating that it is either a nearby young binary system or a member of
the Upper-Centaurus-Lupus subgroup with a 57% probability of membership.
