The signal is split into five separate bands using cross-over filters, and these feed the side-chains of five separate compressors. But the filtered signals are not mixed back together again: instead the gain modulation signals from all five compressors are matrixed into modulation signals for 4 dynamic shelving filters plus a gain stage.
To put it another way: while this plug-in behaves like a multi-band compressor, and allows you to solve many of the same problems, it is in actual fact a constantly changing 4-band equaliser, and when it isn’t doing anything, it really isn’t doing anything!