  We present updates from QCDSF/UKQCD/CSSM on the $SU(3)_f$ breaking in $B$
meson decay constants. The $b$-quarks are generated with an anisotropic
clover-improved action, and are tuned to match properties of the physical $B$
and $B^*$ mesons. Configurations are generated with
$\overline{m}=(1/3)(2m_l+m_s)$ kept constant to control symmetry breaking
effects. Various sources of systematic uncertainty will be discussed, including
those from continuum extrapolations and extrapolations to the physical point.
We also present new efforts to calculate $f_B$ and $f_{B_s}$ using weighted
averages across multiple time fitting regions. The use of an automated weighted
averaging technique over multiple fitting ranges allows for timely tuning of
the $b$-quark and reduces the impact of systematic errors from fitting range
biases in calculations of $f_B$ and $f_{B_s}$
