daiva is the result of past actions (pūrva karman). Past actions are ultimately past efforts (pauruṣa). As efforts, past and present efforts do not differ in their nature. As they do not differ, it is possible to conquer the results of past actions by stronger counteractive measures (para-pauruṣa) of today. Therefore, past karma can be overcome by human effort. It is not inescapable. It cannot be  predicted by daivajñas as they cannot know the efforts a human might or might not be willing to take. For, it is a matter of free will, and that is also a matter where the whole topic becomes really interesting.

The opinion of the author of the MU seems to differ only by degree from the general consensus of Indian astrologers, then: he claims that all effects of past action may be counteracted by present action; they say that some effects (adṛḍha-karman) may be so counteracted, while others (dṛḍha-karman) are too powerful and therefore must take effect. Both operate within a framework of karma theory.

In the case of a person who is not willing to make any great effort to change his 'fate', then, I suppose our author would agree that the person's actions from previous lives will largely determine his present one. The question that I am really after is this: would he then accept the celestial mechanics studied and interpreted by astrologers as accurately reflecting such karma-phala? But perhaps that is not a topic that comes up in the MU.

Best wishes,
Martin