Siren, Transcending tone application

Glad I found this forum, this is great! I'm going through Jaime Vendera's Raise your voice, doing the Siren and Transcending tone(mesa di voce) exercises. I'm not exactly sure how you apply exercises like these to songs you are learning. When you reach the top of your unstrained chest voice, are you supposed to start mixing back towards head until you are strong enough to just do chest? I don't really do any maroon 5 type stuff(where I guess this would be valuable to switch around from chest and head) I do sing more stuff like the strokes and kings of leon where it is mostly high chest. Any insight on how to develop this part of the voice would be awesome. Exercises( as of now) posted below. Thanks!
https://soundcloud.com/mikeylikesit182/ ... oud11-7-14
https://soundcloud.com/mikeylikesit182/ ... oud11-7-14