__ late answer but maybe some other people need this.
Gaia does not change TweenMax defaults. I had the same thing. The way you can do this is writting nessessary line to begining of your code like;
OverwriteManager.init(OverwriteManager.AUTO);
or for just one tween.
TweenMax.to(mc, 1, {x:100, overwrite:5});
for mor info:
http://www.greensock.com/overwritemanager/