I visited here today after stopping at Clach a' Mharsainte nearby. I first spotted this stone on the 1867 OS map, and haven't found any reference to it anywhere else. I originally listed it as a standing stone, but it is in fact a earth-fast flat-ish boulder. It was covered in two inch-thick moss, and I tried to scrape some away, but the heavens opened and it would take a while to clear the whole stone, so I left it. I've changed this site to Natural Rock Feature until someone can investigate further, but I wouldn't be surprised if under all that moss there were some cup-marks.
Directions - head N out of Pitlochry, past the Faskally caravan park on your left, until you see a sign for Loch Tummel & Queen's View to your left, over the Garry Bridge. Go over the bridge, and follow the road past Loch Tummel and Dunalastair Water to Kinloch Rannoch. Follow the road through Kinloch Rannoch as it curves round to the right at the head of the loch, and after about half a mile you'll see the huge timeshare complex to your right. Go past this, and park at the "patrons only" car park a wee bit further on on the left, which I'm sure it would be ok to use for a flying visit! If not, you can always park in Kinloch Rannoch and walk out, it's not far.
Walk west (the direction you were heading in) from the car park for maybe 100m, passing the marina and an outdoor centre hut on your left. Just beyond here, the timeshare buildings come to an end on your right, and there's a dry-stane wall heading up the hill. Looking up beside the wall you'll see a small wooden "kissing gate" - climb up and through this (watching out for the thorns!) and you'll find the stone up a few metres to the right, covered in thick moss.