Stereo Mode exact meaning

[sdmorvan]

Dear all,
anyone could help understanding what is the exact meaning of the different stereo modes?
For example: if I use only one channel (i.e. the Left one) in Stereo Linked mode, or in L/R mode, the amount of applied gain is different (I would say in L/R mode the filter have 3 dB less gain).
Is it intended to be so?
thx!