First - if you're running Alt-F firmware you might be better off asking on their support forum, because generally speaking it's the firmware that dictates how the unit responds.
Second - regardless of what the drive is used in - how head parking affects the LLC is going to be determined by the frequency with which you access the drive - if you access the drive once a day, and run a backup job that takes an hour (which is essentially what I do), an 8 second park interval is neither here nor there, but if you're accessing the drive every few minutes (for example, streaming music), it's going to be parking the heads and then reloading them very often.
Personally I think 8 seconds is way too short but what do I know ...