What size(girth) screws and which plugs? Adding more battens will likely be hard to get exactly in the right spot to properly distribute the load. If you have them too high, it will want to lift off the top battens. Too low, it will pull down more on the top ones. I would have thought you'd be fine. I've seen kitchen units that hold (far too much) crockery hung by less. But then, @Bobbo could likely weight in and tell me I'm talking bollocks, which I'm fine with.
What size(girth) screws and which plugs? Adding more battens will likely be hard to get exactly in the right spot to properly distribute the load. If you have them too high, it will want to lift off the top battens. Too low, it will pull down more on the top ones. I would have thought you'd be fine. I've seen kitchen units that hold (far too much) crockery hung by less. But then, @Bobbo could likely weight in and tell me I'm talking bollocks, which I'm fine with.