I also wanted to add, this applies to non-TL positions as well...mostly the old "specialist" positions, mmb, gsa, cash office, receiving, signing, etc.
I had to interview for my signing position, but it was more of a formality, I already had the position because the STL, ETL-HL, and the TL all wanted me.
It's all about having the support of the key people who oversee you.