"Ms. Hilton has been cooperative since her incarceration," says spokesman Steve Whitmore. "Her good time/work time credit is accruing."

The 26-year-old heiress is serving a 45-day sentence for violating probation in an alcohol-related driving case. With those good behavior credits, the sentence drops to 23 days, putting her on a schedule to be released June 25.

Hilton was recently transferred to the medical clinic of the women's jail in Lynwood, Calif., from a downtown Los Angeles jail hospital.

"Her assessment is ongoing," says Whitmore. "Her condition is still stable."

"From here," he adds, "it will be determined by medical staff whether an inmate can be moved back into the original module (cell block) where they were before. I don't know when that day will be, it's a day-by-day situation."