I know what you mean. There's a different taste for me when I use the GOSM or the electric Lil' Chief compared to the UDS, Kettle, or WSM. There is also a big difference between the all wood taste that comes from when I use Dad's Bandera clone.
The fuel source has a lot to do with it as does the amount of smoke and especially the lack of the "grease flavored smoke" that can come from cooking on a UDS.
I don't think you've done anything wrong all along. Just did something different. Different is good.
You will get different results and flavors from coal, gas, electric, and wood. That's the beauty of having all them options at your disposal.
I'd say the real question is, will you stick to the cookshack or go back and forth and use the kettle and UDS as well.
Bob