Thank you Steinberg for including different relative value modes.
As I see it, the downside with using Absolute MIDI CC values is the limited resolution of 7 bits (0-127).
Using an encoder that sends Relative MIDI CC values can potentially overcome this limitation.
Unfortunately, Cubase 12 currently does not take advantage of this as the scaling of the controller value to its destination is fixed and cannot be altered.
Example 1 (Absolute CC value):
The controller sends CC values between 0 and 127.
The smallest change in value at the destination (the parameter you want to control with your MIDI Controller) is always going to be MAX_RANGE / 128. So if the parameter you want to control can be between 0 and 100.0, then the smallest step will be 0.78125 (100 / 128). Changing the parameter from say 50.0 to 50.5 is therefor not possible with an absolute MIDI CC value.
Example 2 (Relative CC value):
The controller (a rotary encoder) sends relative CC. Turning the encoder clockwise, it sends a value of +1. Turning the encoder counter-clockwise, it will send a value of -1.
The encoder does not have a fixed range as the the controller in the previous example (0-127), meaning a scale has to be superimposed.
Lets say you want to control the Gain value of EQ1 of the channel strip with your controller. If the value for Gain can be between -24.0 and +24.0 and you are using a controller that sends absolute CC values between 0 and 127 the effective resolution would be 0.375 Gain per CC step.
Switching to a relative encoder, that does not inherently have fixed range, it seems Cubase is scaling each CC step as if it was an absolute value. This means that you are stuck with the same resolution of 0.375 Gain per relative increment/decrement.
Include a setting for scale factor or range when using Relative Value Modes.
Using an encoder that sends relative MIDI CC as in example 2 and by setting a user defined value for scaling range to 1,000 for example, the resolution has now increased from 0.375 / MIDI CC to 0.048 / MIDI CC.
Not being able to define the range (or scale) of a relative controller message takes away its greatest advantage - not being constricted to a 7-bit (0-127) value.