लिङ्निमित्ते लृङ् क्रियातिपत्तौ

Where there is a reason for affixing लिङ् (Benedictive) the affix ऌङ् (Conditional Future) is used in the Future tense when the non-completion of the action is to be understood.
The words 'in denoting future time' are here. The reasons for affix लिङ् are such as cause and effect &c. mentioned in sutra 3.3.156 and 3.3.157 &c. The लृङ् is called the conditional tense. "It comes in the conditional sentences in which the non-performance of the action is implied; or where the falsity of the antecedent is implied as a matter of fact. It usually corresponds to the English Plu perfect Conditional, and must, in Sanskrit, be used in both the antecedent and the consequent clauses".-- Apte's Guide.

Thus सुवृष्टिश्चेदभविष्यत् तदा सुभिक्षमभविष्यत् 'if there had been good rain, then there would have been plenty of food; or if there were to be good rain then there would be plenty of food'. It is implied that there was not good rain, nor consequent plenty: or that the occurrence of good rain is dubious, and the desirable consequence equally so.

So also here, दक्षिणेन चेदायास्यन्न शकटं पर्याभविष्यत् 'if he were to go by the right side, the carriage would not be upset'; यदि कमलकम् आह्वास्यन् न शकटं पर्याभविष्यत् 'if he were to call Kamalaka (which he will not), the carriage would not be upset'; आभोक्ष्यत भवान् घृतेन यदि मत्समीपम् आगमिष्यत् 'you would eat food with clarified butter, if you (were to) come to me (but you will not come)'.

All these sentences refer to future time. The non-upsetting is a future contingency and is an effect the cause of which is the 'calling of Kamalaka'. The speaker--having apprehended the cause and effect, and having also learned from other sources that such an effect will not take place, that is to say, that Kamalaka will not be called, and the carriage will be upset-- has employed this conditional tense to express his idea. The whole sentence यदि कमलकम् &c. really gives this sense:-That both actions, 'the calling' and 'the non-upsetting', which are subjects of a future time, and which are related as cause and effect, will not be completed; that neither Kamalaka will be called, nor the impending fate averted from the carriage. The sutra may also be thus rendered according to Professor Bohtlingk:- In a conditional sentence, which would require a Potential according to 3.3.156, is used, if the sense is that of Future time, the Conditional Tense, when the action is not complete.