  We study the excited $B$ mesons' contributions to the coupled-channel effects
under the framework of ${}^3P_0$ model for the bottomonium. Contrary to what
has been widely accepted, the contributions of $P$ wave $B$ mesons are
generally the largest and this result is independent of the potential
parameters to some extent. We also push the calculation beyond $B(1P)$ and
carefully analyze the contributions of $B(2S)$. A form factor is a key
ingredient to suppress the contributions of $B(2S)$ for low lying bottomonia.
However, this suppression mechanism is not efficient for highly excited
bottomonia such as $\Upsilon(5S)$ and $\Upsilon(6S)$. We give explanations why
this difficulty happens to ${}^3P_0$ model and suggest analyzing flux-tube
breaking model for the full calculation of coupled-channel effects.
