Driver version can have an effect on hash rate. Though from personal experience, it's usually negligible. I'd guess the reason you see older versions in the benchmark data is mainly that it doesn't pose any benefit to do frequent driver upgrades. It'd just be wasted time. Especially for a rig which has many GPUs and a weak CPU. Upgrading can take a long time in certain cases. And then there's the risk that the newer driver will be buggy or introduce new problems.

"If it ain't broken, don't fix it."

As for neoscrypt profitability, multiply 0.45790 by your hashrate in MH/s, and the result is the value you would receive after a day of mining if that profitability estimate holds true, measured in milliBTC or mBTC. If you're being paid in something other than BTC, you'll get the equivalent amount of that coin when it's added to your balance.