Is it valid if the due date for the Dinar precedes the performance of the service in a Mukataba contract?

Primary text

If the due date for the Dinar is set before the service and the service does not immediately follow the contract (meaning the Dinar is deferred and the service occurs afterward), the contract is valid. If the service immediately follows the contract, it is inconceivable for the Dinar to precede it, and immediate payment at the beginning of the contract is impermissible because immediate payment (Hal) requires deferment as a condition.