  We systematically study the top-down model of loop quantum black holes
(LQBHs), recently derived by Alesci, Bahrami and Pranzetti (ABP). To understand
the structure of the model, we first derive several well-known LQBH solutions
by taking proper limits. These include the B\"ohmer-Vandersloot and
Ashtekar-Olmedo-Singh models, which were all obtained by the so-called
bottom-up polymerizations within the framework of the minisuperspace
quantizations. Then, we study the ABP model, and find that the inverse volume
corrections become important only when the radius of the two-sphere is of the
Planck size. For macroscopic black holes, the minimal radius obtained at the
transition surface is always much larger than the Planck scale, and hence these
corrections are always sub-leading. The transition surface divides the whole
spacetime into two regions, and in one of them the spacetime is asymptotically
Schwarzschild-like, while in the other region, the asymptotical behavior
sensitively depends on the ratio of two spin numbers involved in the model, and
can be divided into three different classes. In one class, the spacetime in the
2-planes orthogonal to the two spheres is asymptotically flat, and in the
second one it is not even conformally flat, while in the third one it can be
asymptotically conformally flat by properly choosing the free parameters of the
model. In the latter, it is asymptotically de Sitter. However, in any of these
three classes, sharply in contrast to the models obtained by the bottom-up
approach, the spacetime is already geodesically complete, and no additional
extensions are needed in both sides of the transition surface. In particular,
identical multiple black hole and white hole structures do not exist.
