This change was introduced by Maxime Gouzevitch and his comment below:

This is a feature. Those lines was designed to decide if a detailed shower tail
shall be used or not. It is a question of speed vs details. It looks like in
version before a detailed shower tail was always called and the condiotion line 390
was useless. Now it allow to decide if one need or not detailed shower tail.

Florian may explain better the point why those lines have to be changed: