My pivot chart has the wrong Y axis values but correct data point values

"Very strange indeed. Have you tried moving the chart to a new sheet (ie so it is a chart sheet, not an object on a worksheet)?
What happens if you change the chart type to a column (for example)? and back?

The lowest (blue) series seems about right - the $19 is just below the $20 gridline. The spacing between them also looks OK - 11, 13, 10. Except the 19 would be a little low compared to those space values, as if the Y axis did not have a true zero.

Daft question time - why use a Pivot Chart at all if you have all these data points? Why not go for a standard XY chart?

What Excel version is this? (looks like 2007, but could be 2010 I guess)
Can you share a (sanitised) version of the data?"