The most you could loose would be the elevation difference from the tap to the lateral at that spot. Even if you went straight up with the drop and had less than 30 feet of drop from the lateral to the discharge you would loose about 2 inches in vacuum at most. If the 5/16 is full there would still be some vacuum created. If there is 30 feet or more elevation drop from the lateral to your discharge there would be no loss. It does not affect the vacuum in the lateral so there is no compounded loss from tap to tap.