....Looking at the specifications on the Peak Atlas Pro....
You have avoided the non-problem but the remaining one is that you have been misled into thinking that mA current testing can tell you much that is useful about the 15A current device in your hand.
I have a DCA 75 myself and beautifully designed they are, with their slick, compact graphics and curve drawing software. Too bad it's really only of use for small signal devices just like your DMM or those really cheap Ebay component testers. In electronic measurements and servicing, the curve tracer (a rare and mighty expensive oscilloscope and high power test jig) is the recommended way to test power transistor parameters. For me, that counts out proper testing and leaves simplified tests at fixed currents and temperatures as the only way to compare and match parts.
There are many repair threads that either are about or refer to both professional and rough methods of matching BJT output transistors - there's even a DIY, PC driven curve tracer kit by member locky_z here
http://www.diyaudio.com/forums/vendors-bazaar/205733-intelligent-curve-tracer-3-0-release.html
In the real world, not many amplifiers are now built with matched components. Matching by using parts from the same tube package is now reliably good enough for output transistors on new equipment and replacements - as long as any transistors in parallel are all replaced at the same time. Getting more fussy than that will not improve your audio - it only calms anxieties about non-problems. Maybe you can't afford a tube of 25 transistors but you could ask your supplier to do that selection, if he buys in that form.