Board Thread:Questions and Answers/@comment-27003142-20160217210943/@comment-26347196-20160217233902

The Flowey part at the end might say otherwise to me. In the True Pacifist route, the barrier is still broken, and the endings can be branched into Frisk living with the monsters or elsewhere. After that Flowey comes and talk to you. It may be in a place as far-fetched as in a dream, or in another kind of dimention (i.e The loading screen?), but it does not seem to be in the barrier, since that barrier is broken.

Which could lead the the fact that in the neutral ending, Frisk's encounter with Flowey may not be happening in the barrier.

My guess would be the loading screen, given Flowey does have the determination power before, but is supressed by that of Frisk/Chara (explained in the Genocide route), thus he had the power to access to the loading screen but lack the power to actually access his own save file (Until the Omega Flowey segment).