Will update as more details are being revealed. If its anything like last year, chances are the signing/autograph session will come with the price of the VIP ticket which also gives you front row view of the concert.
As for the format of the autograph session, last year there was some hoo-hah for the May'N's autograph session because the organisers implied there will be an autograph session but what we got instead was just May'N giving out pre-signed white boards to fans while she shook their hands. Requests for photos and impromptu signing of any other merchandise were not allowed much to the ire of fans. Hopefully this will change this year and they will allow fans to bring their own merchandise to be signed. So i think you'd want to take that into account for your trip to Singapore, since those other concerts you're attending sound much more awesome-er.