Staining the side of our house seems to be an ongoing process. Every year we attack more of it, catch up on some and give an extra dose of stain elsewhere. The challenge was compounded this year when we added an addition that blends new boards with existing 30 year old siding. Well, just try and match those colors! So, my husband has diligently added coat upon coat, returning to the store frequently for fresh gallons of stain. Last weekend, the same stain went on the house, but it had a shine to it. I freaked. What had changed in the formula? Can they change it without telling you? Of course, I thought, that's why they always advise you to buy enough for the job. Another thought: Could it be ponding on the surface or "flashing?" I'm not really sure where the answer lies. All I know is that I want it to dull out and look normal again. Experts promise that weathering will take the sheen away. I'm not at all sure, especially since it's never happened before. Any thoughts?