Hayanaratna 1.166

Here the time correction is told because the year Sun and the birth Sun do not match. But take the karana (short handbook for planet maths) one has studied. By it, the true birth Sun is corrected for one's own place, east-west and north-south. The yearly true Sun is corrected by that karana for longitude and the rest. Then it is surely equal to the birth Sun. Then the match is ... (Our text is unclear here: the last word, telling how the match is shown, cannot be read.)

Simple meaning: Why no correction: with one's own manual and place corrections, the year Sun always equals the birth Sun.