I have recently applied 3 coats of Bona Traffic over one coat of Bona Prime on to 30 jarrah (ie. an Australian hardwood) stair treads. The problem I have is that the finish seems very soft - much softer than on some similar treads I did a few years back with Bona Mega. The finish seems to mark and scratch very easily. I tried to follow the instructions rigorously, so I can't fathom what has gone wrong. The finish was applied between 2 months and 2 weeks ago, so I would have expected it to fully cure by now. I was only mixing small quantities at any one time - typically 300 to 400 ml of the Traffic plus 30 to 40 ml of hardener. I have a suspicion now that maybe the amount of hardener was a little less than anticipated, since I now have about 1.3 litres of Traffic remaining out of 4.5 litres, but with about 0.18 litres of hardener remaining out of 0.5 litre. This would seem to imply that I have used only about 8% hardener instead of the 10% suggested in the instructions.
Could this lead to such a dramatic reduction in hardness for the finish? What should I do now - sand it all back and recoat again, or just overcoat? It is difficult to measure exact quantities in such small doses, so is it better to try and overcompensate with more hardener next time? If I use excessive hardener will this lead to other problems? Your expert advice would be much appreciated. Thanks.

BONA makes a mixing bottle to mix smaller amounts of Traffic and I would recommend using that when mixing small amounts. Personally, I would try recoating the stairs instead of refinishing them with two more coats. It's possible you got a bad batch or didn't use the correct ratio of finish and hardener, which would effect the durability. Also, Traffic has been reformulated and personally, I think the newer stuff is not quite as durable as the original.

Is there a better alternative in your opinion?