Rushing the timing is usually a result of falling into the heel turn rather than rising into it.
From a simplified perspective, a heel turn has an early rise because the lady must straighten her leg and "stand up" as she arrives over the foot, so that her second step swings only to closed, and not through. The man gets her to straighten her leg as she arrives by straightening his own.
Even once she can sort of do a heel turn, the lady may need to practice to get used to carrying the momentum she entered the heel turn with, through the heel turn, and on into the crossing steps past the man that finish the figure - many ladies tend to stop and wait at the end of the heel turn. The man is still leading, be he cannot make the lady go past him, since he is in a weak position spinning on the ball of his foot. What he can do is time the lowering so that the couple will be down when the lady has completed the amount of turn he wants.