This is absolutely right, but when we mining DGC and WDC it should be that way. Just look in to profitability charts, WDC and DGC has very high stales rate, thats why we have so many "rejected". But profit still very high.
My profit calculation takes both (actual) stales over past few minutes and orphans over last 100 blocks into account for all currencies, and also subtracts an additional 10% from WDC and DGC. I believe it is more accurate than coinchoose.
Besides that, WDC and DGC offer more consistent profit as we can find blocks very quickly and will not be subject to variable block times as much as on FTC, LTC, or NVC.