The signature didn't play a role for the merit I got at all. In the very beginning I joined a project which turned out to be scam and of course I didn't got paid, lost a few months and decided not to join any campaigns as they were waste or time and the merit system came in the meantime. Then I was wearing no paid signature for a couple of weeks then joined one project of Tokensuite as I thought they were reliable, but unfortunately another disappointment.
Finally found  a campaign by izanagi narukami,  which was  only two or three weeks but I finally got paid.
During all that time I was receiving merit without any problems.
So the conclusion:  no matter if you are with paid signature for altcoins/bitcoins or without signature at all the merit are coming because of the content you are posting.