mark
+1y
Yep. You actually have less camber when you flip the lower balljoint and leave the upper stock. This is because your lower arm is at a "lower" position through it's range of travel, thus kicking the lower part of the wheel IN, which gives you less camber angle. But if you flip both lower and upper, you pretty much get the same camber as stock. This is because you're moving the upper arm and lower arm "down" the same distance. We're talking half a degree of camber here, so I really wouldn't worry about it. If you want less camber, pie cut your upper arm.
What it messes with is the instant center in the front. Mazda set this from the factory so that the upper arm angle, lower arm angle, and tie rod end angle meet in a single point. Now that the lower arm angle has been tampered with, it is not the same. What I've noticed from personal experience is increase in bumpsteer, but it's still pretty stable to not be worried about.
To me it's worth flipping your balljoints for that extra drop if needed. Just make sure you use new bolts and watch the arm just in case it begins to bend at the tip because of the removed material.