edit: mcfinlay has suggested below that there may be some sort of automatic resizing going on due to the width of the Los Angeles map. I have removed it for now until I can verify why this is happening
Ok - I will use this post and only this post to discuss any scale issues. Below is what I feel should remove any doubt that the maps, in particular LA are out of scale. Please let me know if you disagree.
Before you look at the below images, we should agree on one thing. If, say, 10 miles is a certain distance on 1 map, and exactly the same distance on another, then those two maps are of equal scale. That being the case, the image I have here is designed to demonstrate that (using the two maps that have been contemplated above, LA and Houston).
At the top of the image, you'll see two 10 mile long measurements, copied directly from the two images below them. Clearly the two lines are of equal length.
The two larger images are basically carbon copies of the main maps you've seen earlier in the thread, I've added the altitude at the bottom of each so you can clearly see they are consistant with my zoom level. I have done the same with multiple other cites (Paris, Quito, Auckland), all with the same result.
Hopefully this answers the questions regarding scales.