Iirc, on some models of DSP (6k?), left and right were asymmetric in shape so a centre had to be different again. As well as above answer, with DSPs that are symmetrical, Meridian are just treating them part number wise (pair vs VC) the same as their asymmetrical models.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).