What temperature are you fermenting at? That actually has a lot to do with the production of sulfur out of these lager or pseudo-lager yeasts. If you are close to the high end of its range, it will take a bit to age out, but it will go away. The closer you are to the low end, the less sulfur production you will get out of it. Do yeast washing and use that for your next Kolsch. Make a semi-large starter and make sure you start out at the bottom end of the recommended fermentation temperature. After you do this, you will experience first hand the difference that fermentation temperatures make.
Also, whatever tastes/smells are there at bottling, those are the tastes/smells you will be stuck with (generally speaking). Also, during the aging process, the more yeast cells there are, the more chemicals that the yeast can reabsorb. This is why keeping on the cake for a full month before racking or bottling is not a terrible idea for beers that need to be aged.
And before autolysis comes up, that is from the yeast dying. Think about the expiration dates on the yeast packages for that. When hitting a steady final gravity, that's the equivalent to the manufacture date of the liquid yeast package. Depending on how healthy the yeast are, you have up to six months before the yeast die and begin to rupture (autolysis).