  We study 23 previously published Kepler targets to perform a consistent
grid-based Bayesian asteroseismic analysis and compare our results to those
obtained via the Asteroseismic Modelling Portal (AMP). We find differences in
the derived stellar parameters of many targets and their uncertainties. While
some of these differences can be attributed to systematic effects between
stellar evolutionary models, we show that the different methodologies deliver
incompatible uncertainties for some parameters. Using non-adiabatic models and
our capability to measure surface effects, we also investigate the dependency
of these surface effects on the stellar parameters. Our results suggest a
dependence of the magnitude of the surface effect on the mixing length
parameter which also, but only minimally, affects the determination of stellar
parameters. While some stars in our sample show no surface effect at all, the
most significant surface effects are found for stars that are close to the
Sun's position in the HR diagram.
