monero.crypto-pool.fr --> Pool Efficiency: 113%
It means that we find more blocks on average than other pools or solo miners.
I would definitely mine at you pool again, if you have merge mining.
Do you have plans in the future to do that?
No I didn't think about it. Let me see what I can do.
EDIT : it seems that merged mining lower the overall hashing speed resulting in lower gain...
That's impossible. Miners give zero shits what you tell them to hash, they just hash away. If it would lower the hashing speed, that's a problem with your implementation - not a problem with merged mining.