Curious that Cell is used as a measuring stick to gauge Pan's strength. Very cool.

IF she is indeed stronger than Perfect or even Super Perfect Cell, then it is clear as day she inherited the Mystic/Ultimate form from her dad and would explain the seemingly inability to go Super Saiyan despite the power-level that she is claimed to have requiring a corresponding Super Saiyan form:

Super Saiyan 1 grade 4 for Perfect Cell level.
Super Saiyan 2 for Super Perfect Cell level.
Super Saiyan 3 for Buu level.

Again, this theorem depends on Pan being actually as strong as her proponents claims she is.