OHC on an orange pad is an aggressive approach, so if worked correctly I would be surprised if it was doing nothing in the way of removing the swilrs... How large an area are you working at a time, and for how many passes? I would step yuor area down to 1' sqaure on very hard paint, ideally with a 4" cutting pad, and work the polish for several minutes on each area until the residue goes clear.
Ideally, a Paint Thickness Gauge would be very useful here to see just how much paint yuo are removing with each set of hits with the OHC. The reason I say this is that, if the car has at any point been resprayed badly, some of the swilrs you are seeing may well have been flashed in below the clearcoat in which case they wont be coming out... This would explain why you are seeing no improvement in the swirls, as while it may take a couple of hits of OHC, I would expect to at least see an improvement.
Check you technique for apply the polish first and see if you can get a handle on the recent history of the paintwork - any resprays?
Also, if these swilrs are deep, significant paint removal may well be required and I wouldn't venture down this road without a PTG on hand to gauge whether or not this is safe.
