...roof tiles going all the way down, so basically cutting of the small border triangle at the bottom. (hope you understand what I mean...)

Not sure. The roof modules were hastily designed and kept simple for a very specific building. Simple elements that do not have too much geometry to interfere when combining sections. That, of course, means a couple of compromises - and lack of elegance and detail.

If I get your point, your alternative would be something like this (same thread SF):
roof_bnl_special_notxt.zip

But it is no longer a match with the other roof elements...

ok

PS Basic geometry like this can be made with pretty much any tool - including the Generate 3D shape plugin (see thread 6600) - or even by drawing walls in SH3D, exporting as .obj and import/rotate.