I agree that the timing isn't a big deal, but you should pay attention to the fraction of their stock they sold: If they believe the stock price will be going up, they'll sell a smaller fraction of their shares than if they believe it's peaked.
For all we know, they're each getting thousands of more shares, in the near future, as part of their comp plan.
Keep in mind, selling shares (and working hard to make the stock price grow), is essentially part of their pay plan. They probably have relatively low salaries, and the Apple board expects them to sell stock in order to make their overall salary package competitive with similarly-paid positions in the industry.