| Hey Bass Dan,
I can be mistaken, but maybe it seems louder because you hadn't really played it much at all in 2 months until you lowered them. Or maybe it was technique and having higher action prevented you from playing with fluidity in the hands and arms that is neccessary to get full sound on any string height, especially the really high string heights.
Having lower action is definitely easier (for me atleast) to getting into the feeling of being loose and fluid. Then the trick is to apply that feeling of playing as you raise the strings. You should notice the sound will be louder and fuller, but as I am learning through everybody's most appreciated posts, do not put it higher than you are comfortable, and don't be intimidated by bassists that have higher action. We're talking about 2 different people, with different hands, with different basses, and possibly different strings. All these have their affects on the overall sound of the instrument as well as to the string heights neccessary for personal comfort, personal taste in tone from particular string heights, etc.
As for set-ups, Upton is supposed to do good set-ups, especially for bluegrass. So you're good for that. But even after a bass is set-up professionally, you shouldn't be affraid to adjust the action yourself to suit your playing style and comfort, or especially when the weather around you is changing. I always have to bring my strings up half a turn or more in the winter when the wood dries from indoor heating, and lower in the summer when it gets really humid. the 2 wheels should be adjusted the same ammount of turns each. Not one more than the other. If you don't get any buzzes on the E string or on any string for that matter, than don't worry about it. The E probably really is higher than the other strings if you look at the bridge relation to the fingerboard arc. If you have a buzz, don't adjust one wheel higher than the other, instead take your bass to a professional luthier and get the bridge reshaped. Or maybe the problem can be in the fingerboard, or in a combination of both. At that point, take your bass to the luthier and let them do their work. Just because you got a bass set-up today, in a year or too you might have to take it to the luthier to get it set-up again. Wood moves, fingerboards wear out, etc.
I've been told that gut strings (a bluegrass or slap bassist choice of string usually) need more height to allow the strings to fully vibrate as well as to get the neccessary volume in playing. This is apparently because gut strings are apparently really soft on the hands and low on tension. That is to say that a bass with LOWER ACTION but high tension STEEL strings can feel more difficult to play than a bass with HIGHER ACTION but significantly lower tension strings like GUT STRINGS, or synthetic core strings.
As for technique, I think it's important you find a teacher, and even if you take a lesson once a month or so. It's extremely important to have some guidance to correct bad habits before they develop into physical problems.
I hope this all helps, and I thank everybody for their help on the matter. If anyone has anything more to add, you are always welcome.
Mike | 
