Consulted with Dr. Sybren🐱 @dr.sybren via support chat (under name "Kite"); was told to file bug report after he checked .blend file.
Complete walkthrough of problem available here:
Windows 8.1 GTX 755m (i7 processor)
Broken: 2.79 5bd8ac9
Short description of error
Playback of audio in VSE does not mimick rendered audio. Audio renders at a much higher amplification than what is heard on playback. If you engage in changing the volume values of a medium/large waveform in the strip's menu (N) from 1.0 to 10.0 this is readily apparent. Rendered audio often clipping. Master volume in render options presents solution to fix issue, but unknown what value to set at without trial/error. Issue with audio strips with keyframes not rendering though when large file rendered (unable to produce .blend sample at this time, will not open ticket for this problem at this time). Mixdown seems to solve problem above, but mixdown has no mastervolume control thus clipping occurs. Opening a new scene in the project and importing project as scene clip allows you to change mastervolume, potential workaround method. Trial and error then used to set a mastervolume that will not clip rendered audio. Otherwise individual strip volume levels, those with medium - large waveforms, must be manually kept close to a volume of 1.0 in order to avoid clipping, regardless of what is heard in the vse playback.
Exact steps for others to reproduce the error
-Engage VSE playback, listen to the 3 sets of audio strips at speaker volume (each is same strip set to different volume levels). No clipping should be apparent.
-Mixdown/render audio out.
-Check waveform in audacity/audioeditor of the 3 portions and confirm clipping occurs
(easily repeatable inserting any audio track in a new .blend file so long as the waveforms are similar size, otherwise value of 10.0 volume should be decreased/increased to mimick)