Lindsay Lohan -- She Got Community Service Credit for Performing Onstage!

Lindsay Lohan and her community service organization are trying to bamboozle the judge into giving her credit for time she spent performing onstage ... we've learned that's exactly what the prosecutor will say in court today as he argues she's violated her probation.

Law enforcement sources tell us ... prosecutor Terry White has combed through the 240 hours at CSV -- the London-based community service organization. White will tell the judge ... on one day Lindsay got 6 hours credit, but he says 2 of the hours were for her matinee performance and another 2 were for her evening performance. The remaining 2 were for a meet-and-greet afterwards.

And we've learned White will tell the judge on another day CSV represents Lindsay did community service from 11 AM to 3 PM. Problem is, White says he contacted producers and the play started at 3 PM that day. Lindsay lived 6 miles from the theater and had to show up at least 35 minutes early.

We're told White also scoffs at credit Lindsay received for throwing a fundraiser for CSV, arguing community service is supposed to be for the community and not the organization. And White is concerned about the story we broke -- that Lindsay lobbied Esurance to donate $10K to CSV -- saying it creates a conflict for CSV which is supposed to scrutinize Lindsay and not become beholden to her.

White believes there are enough irregularities to call all 240 hours into question.

White wants the judge to violate Lindsay's probation based on CSV's records and will ask that Lindsay be present for a hearing to determine what, if any consequences should result.

We called Lindsay's lawyer, Shawn Holley, but so far no reply.