while you wait for answers and need it to work without nasty distortion artefacts:
press EDIT go to GLOB page. there is a pad in and pad out. there you can scale, how your input drives the program and compensate with padout for the gainchange. best way to make precise adjustements is, to click on the pad numbers, they should appear white now, then go to the second fader and move with shift pressed.
when you do it in vst analyzer, you can see the changes immediately and also see, when the program "behaves" right.
then press exit to go back to the prog page. there you have to press save, if you want the program to keep your changes.
maybe this helps until the problems are sorted
system 1: windows 8 32 bit - samplitude prox/x3, tracktion6/7, reaper system 2: mac osx yosemite - reaper(32+64bit), tracktion6/7(32+64bit)
both systems on: macbook pro (late 2009), core 2 duo 3,06 ghz, 4 gb ram, graphic: nvidia geforce 9600M GT 512 MB