Not knowing all the facts...if she was sentenced to 45 days in jail, she would serve the remainder of the 45 days less time served. I am assuming that the sentence was adjusted to allow her to do weekends. Between corrections and the court it may revert to the straight 45 days. I do not believe this would be a violation of probation as she is technically still in jail.
This response is based on information provided. Many variables may exist that can only be addressed in an interview. This answer in no way creates an attorney-client relationship.
Your daughter cannot get a sentence of 1 year and 6 months without returning to court on a Hearing to Show Cause whether or not she Violated Probation. At that hearing she would be given the opportunity to have a Public Defender or hire Counsel to defend the allegations. If she were guilty she could mitigate the reasons why the reimposition of the full back-up time is not necessary. Since that did not occur, I believe my learned friend Ed Tidings has addressed what occurred above.