In effect, the scale ranges from −20 VU to +3 VU, with −3 VU right in the middle. The meter was designed not to measure the signal, but to let users aim the signal level to a target level of 0 VU (sometimes labelled 100%), so it is not important that the device is non-linear and imprecise for low levels. '0 VU is equal to +4 dBu, or 1.228 volts RMS, a power of about 2.5 milliwatts when applied across a 600-ohm load. So, the green units on the pic are the actual dB units? Is that what you prefer to see as opposed to the sort of mysterious (to me) VU units? FWIW from the Wikipedia: Now if you can get through THAT gobbly-gook explanation my hat is off to you, haha.
It's hard to know what I'm really looking at as I'm so used to dB units, so I was eye-ballling the differences with the VU meter and 'Enhanced Spectrum' Foobar plugin's peak readings and your Dejavu meter ( mod) and at -15db meter preamp it seemed to be around 3 units off from the dB peaks, but as those units apparently differ around 4 units (from what I was able to find out) that may be OK. Hiccup: I wasn't familiar with the concept of VU units vs dB so I had to do some reading on that.