St Germain - I'm not sure if cost comes into it. If both CDG and ORY were profitable it would come down to when the best chance to make money would be.
Personally, I imagine that the primary reason for serving ORY rather than CDG is that ORY is more of a business destination. Prior to the codeshare agreement with AF, BE operated CDG and AF, ORY. I very much expect that both routes were analysed to see just where the yield and performance was better.
In respect of connections, I'm not sure this is as relevent given the distance between SOU and LHR. If it we me, I would much rather take a short drive/train to LHR and fly direct than connect over CDG.....have you been to CDG lately??
