User blog comment:B214/Question & Answers 5/@comment-63.136.113.196-20150525215018/@comment-124.195.116.184-20150528042224

^That's why i think the boosted powers dissapears after Issei releases his strike whether it's his punch or his dragon shoot, the fight with shalba you mentioned does not count because Issei kinda combined his Triaina combo in CCQ form. So it's safe to assume that the boosted power dissapears after one strike.