I'm assuming english is your second language, in which case I won't rag on you for how hard that was to read.
My reason for saying to mount center is that you will notice having more tip than tail in the park, and you will likely notice not having a perfect balance. I know that they don't have a symmetrical sidecut, but mounting ahead of it does not ruin a ski, and you hardly lose performance. I can rip as hard on center-mounted skis as I can on something 4 back from center. Hell, if you're going to say that you shouldn't mount center because of performance loss, than you should always mount at recommended. It's really not about riding switch, it's about balance.
I understand it's up to him, but he asked for advice, and my advice, after having skied a center-mounted, similar ski to the blend in the park and all over the mountain this year, I would not mount them anywhere else.