Because the body and mind are not yet fully developed, after some time one's awareness again returns to the world of the senses- the outer world. As meditation progresses one remains in the state of absorption or awareness of the eternal Self, more and more until finally this awareness of eternity no longer leaves. With eyes open or closed, active or meditating, the awareness of the eternal Self is ever present. This is called Kaibalya or Self-Realization. It is also called the highest form of yoga or enlightenment.
Yoga means union.
The highest form of union is the state of kaibalya samadhi. Yoga also is a form of exercise. These gentle stretching postures help heal, tone and prepare the mind and body for Self-Realization. We do not really know the other ashrams so are unable to comment on them. In charge of Siddhayogashram Swami Narayan Tirtha has also given his blessings to his disciple, Swami Sada Shiva Tirtha, to open this ashram in America.