Running v3.40 here... I've found the scale you select is kind of a subjective thing. It just depends on the degree of resolutuion you want displayed.
I too am looking at a pressure issue that has me a bit perplexed and that is that my elevation plot sometimes does not plot either by time or distance even though dgital altitude readings appear active. Also, both the "pressure plot or elevation plot which ever is selected, display on the "Altitude" page...It just seems these should display only on their own page so pressure or elevation can have their own custom data fields, cause as it stands now they both share these fields and some data is redundant to elevation and some to pressure depending on which you bring up on the "Altimeter Page".
Anyone else finding your elevation plot intermittent in time and distance?