The phenomenon of avoided crossings of energy levels in the spectrum o
f quantum systems is well known. However, being of an exponentially sm
all order it is hard to calculate. In particular, this is the case whe
n the potential is generating a Schrodinger equation of a type which i
s beyond the hypergeometric one. Recently, there have been attempts to
understand this phenomenon in connection with Heun-type differential
equations. The most famous example of this class is the quantum quarti
c oscillator which is governed by the triconfluent case of Heun's diff
erential equation. In the following we consider situations where the f
ourth-order potential has two minima and we calculate the avoided cros
sings of its eigenvalue curves in dependence on the asymmetry and the
barrier height between the two wells. The results are compared with th
ose obtained from an asymptotic approach of the problem for large valu
es of the control parameter that governs the barrier height.