TOctree2 Node bounds


While working on TOctree2 I realized that nodes overlapping. For example my bounds for the whole tree is 5000,5000,5000.
So you would guess that the next level (with its 8 leaves) should be 2500,2500,2500 but in reality it is something like 2619.0012 or so. Basically the nodes always overlapping each others. Is that expected and desired behavior for TOctree2?