It sounds like they are trying to get her to the right level of instruction and matching the best resources to the task. Relative strengths and weaknesses shouldn't matter as much as appropriate instructional level for each area.
Also, consider that math achievement scores can depend more strongly on specific exposure, whereas language arts can accelerate just in context of day to day living (presuming an inherently enriched home environment.) A sharp kid may need very little time in math to advance from say 1st grade to 5th grade because of how much of that curriculum is stuffed with repetition and inductive processes.
