Please take a look at below and provide your precious comments.
Lagna is virgo at 20 degree 47 min..meaning in 7th navamsha. Now Virgo is an earthy sign and navamsha would begin from the 10th sign. Therefore lagna gets mapped to 7th from 10th which is 4th. Therefore D-9 lagna is cancer – sign # 4. So far so good.
Let us now consider the 5th house which is in capricorn. 5th cusp again is 20 degree
47 min..i.e. in 7th navamsha. This will mean even fifth house would translated to cancer in D-9.
Implication is that base signs (1,5,9), (2,6,10), (3,7,11), (4,8,12) all would be mapped to the respectively same sign in D-9. Am I missing something?
I am doing this exercise in the context of Jamini Sutram.

Yes, based on equal house system dharma, artha, kama and moksha trikonas will have 1,10,7,4 houses respectively. That’s why for money, 10th house is very important in D9. As many benefits aspect / be in 10th house of D9, the richer the man can get.
If you use Sripati padhati, you will get different houses.
Dear Srikanth Ji,
Many thanks for clarifying. You also mentioned Sripati system. Would you be kind to advise me when to use equal house system or Sripati system. If it is too difficult to answer here, would you be able to give any reference of books, websites , YouTube videos .
Kind Regards