
Gauss |

No, the extra rounds do not count against daily usage. That would make the feat useless.
What it effectively does is reduces the cost from 1 round expended per round to to 1 round expended per 3 rounds for the price of an action. From levels 1-6 that action is a standard action. From levels 7-12 that action is a move action. From levels 13 and beyond that action is a swift action.
As for how it is used: At the start of your turn you state you are stopping your bardic performance and then it continues for 2 more rounds.
- Gauss

Whipthorn Icescale |

Per Lingering Performance: "Any other requirement, such as range or specific conditions, must still be met for the effect to continue."
Which means that limits on rounds are still in effect when it lingers. The feat is designed to carry on bonuses (barring any other requirements, like rounds available) after you would normally cease your performance.