The Vedantic philosophies – Advaita, Visishtadvaita, Dvaita and others – range from believing that all souls are actually one SOUL – BRAHMAN – to believing that all souls are different but totally interconnected. The entire universe may, thus, be considered as one all-encompassing BRAHMAN or all souls may be considered distinct but connected to BRAHMAN and all the variations in-between.
The purpose of life and the cycle of births is for the individual soul to either shed its illusion of distinctness or to realize the connections completely. If such be accepted, the entire process of what happens to you in life is merely a process that creates the circumstances to help you purify your soul to the extent that the realization of this oneness or interconnectedness becomes possible.
Looked at it this way, what you do in life has the motive of purifying your soul and whether you succeed or fail merely creates the crucible in which the dross on your soul is burnt off. Thus, where you have free will – in your motives and in your reactions to circumstances – are the only items on which you need free will since the only result that you are working towards is in altering as a person! All the rest is incidental.
Thus, your good deeds of this birth means that you have forged ahead as a person and in your next birth you need lesser purification. Prarabda Karma, in this case, works more to create the circumstances – for further purification - that are needed in the current conditions of your soul. So the circumstances of your next birth will well be determined by your motives and actions of this birth but whether more Punya will give you a better life in terms of materialistic values is debatable. It could well be that the purer soul is born poor and the grosser soul is born rich! Of course, the more realized soul could well be more content, while poor, than the grosser soul in its richness!
In the context of these philosophies, a man who claims predestination robs him of free will is like a person, who is put in to counting pins as the first step to becoming a CEO, interpreting the entire universe in the context of how it helps him count pins!!