Astrology is a business like any other and most of the times used to deceive people. There is a very less genuine effort in the interpretation that is reached and is mostly deduced out of common sense and power of observation and conversations that happen around. An example of this is Shastri in the story, who claims that his shastras are powerful and mighty beyond the normal human perception.
But we see him acting on Shyama’s plan in order to pair up Ranga and Ratna. And in this, his shastras did not have any role, but when confronted, he denies that saying he developed on the hints and the shastras indicated it. But the reader can very well conclude, that Shastri had no merit of his own and he could not have done anything to pair Ranga and Ratna without Shyama’s help.