FORTUNE — If you’re Tim Cook, Apple (AAPL) CEO, and you sell the most expensive computing device in every category in which you compete, you have to pay a lot of attention to surveys of consumer satisfaction — or, as Cook calls it, “customer sat.”

So it was a setback last fall when Apple lost to Samsung in one of those J.D. Power satisfaction ratings that Cook so often cites.

It was also something of a mystery: The iPad had scored 22 gold stars to Samsung’s 18 but somehow came in second. (See J.D. Power’s fuzzy math.)

In the follow-up survey J.D. Power published Wednesday, Apple retook the lead — albeit by a narrower margin (830 to Samsung’s 822) than suggested by the five gold stars it scored in four of five categories.

The reason for the discrepancy, as we learned last fall, is that the two attached charts show very different things. Both are based on a survey of 2,513 tablet owners who were asked to rank, on a scale of 1,000, their experience in those five categories.

The results J.D. Power cares about — the ones cited in its press release and illustrated by the bar chart — are derived by multiplying the survey results by a weighting factor: Performance (28%); ease of operation (22%); features (22%); styling and design (17%); and cost (11%).

Those gold “Power Circles” in the top chart are derived from the same tablet survey, but don’t reflect the original 0 to 1,000 scale. Rather, they show where each company’s products stand relative to its competitors — “among the best,” “about average,” etc.

This system usually works pretty well. But from time to time, signals get crossed: The Power Circles say one thing and the overall rating says another, as they did last fall and, to a lesser extent, this spring.

Cost, not surprisingly, is what hurts Apple in these surveys. But Tim Cook can take some satisfaction of his own in J.D. Power’s latest key findings:

– Lower price is the No.1 reason for tablet choice in 2014, with 25 percent of current tablet owners citing price as the main reason for selecting their current brand, compared with 21 percent in 2013.
– Since 2012, the average purchase price of a tablet has decreased by $53 ($337 in 2014 vs. $390 in 2012).
– Overall satisfaction has decreased by 18 points to 835 on a 1,000-point scale in 2014 from 853 in 2012.

MORE: Overall Tablet Satisfaction Declines as More Value-Priced Brands Vie for Market Share