Decaying Mahogony Decking?

I built a mahogany deck about 10 years ago which was neglected (so cleaning or staining). I had applied Penofin when I built it. The decking became almost black in appearance. Three years ago I power-washed, sanded (with a r.o. sander and a belt sander) and applied an oil-based finish (can't remember which one). The wood was so soft that the power washing 'dented' it in places and I never was able to get a more natural color to come through - just a lighter grey. It is still bad and I have recently had the thought to rent a power floor sander (random orbital) and go at it to take off whatever was necessary to reach a natural color wood (3/32 to 1/8"?) It is 5/4" decking with no surface fasteners. I feel as though this aggressive approach is necessary. I would then stain it with a recommended oil-based stain from this wonderful website. If anyone have any thoughts on this I would love to hear it. Thanks!