Well, just be aware that what the machine is producing as far as VCA level is concerned, as would be seen on a proper scope, versus what your ears perceive, are two radically different things.
There are a number of reasons why we might perceive a sound as being louder, even though in actuality it isn't; not the least of which is the fact that we start losing our ability to hear ultrahigh and subsonic frequencies pretty much from the day we hit puberty. Other reasons include how much harmonic content is present or cumulative in the sound as the knee frequency of the sound is increased: i.e. filter tracking settings, AM/FM modulation intensity, amp feedback, etc. Never mind the biases of your monitors, headphones, listening environment, and so on...
Anyway, most of the time, the machine itself is in fact producing a steady, unbiased sound; it therefore falls on the perception and preferences of the sound designer or mix engineer to curb any perceived sonic anomalies. Hence why the default setting on the Tempest (or any comprehensive synth for that matter) is to not presume to apply "note number" to VCA level (or any other aspect of the core sound), as that would be a completely arbitrary move without context. Ultimately, it's up to you to decide whether or not a sound works for your application, and the tools are there for you to change it if necessary.
Cheers!