  We report recent progress in data analysis on the two point correlation
functions which will be prerequisite to obtain semileptonic form factors for
the $B_{(s)} \to D_{(s)}\ell\nu$ decays. We use a MILC HISQ ensemble for the
measurement. We use the HISQ action for light quarks, and the Oktay-Kronfeld
(OK) action for the heavy quarks ($b$ and $c$). We used a sequential Bayesian
method for the data analysis. Here we test the new fitting methodology of
Benjamin J.~Choi in a completely independent manner.
