R, if you read all of Lee's manual you might notice it's mostly about selling Lee's products. Their data is from other sources but has been doctored to conform to their powder handling equipment. If you look at their data you will see quite a few instances where the "never exceed" load and the "starting" charges are the same or very close. While they list a lot of powders for each bullet they load, not all of those powders will be a good choice. And, since they are getting their data from different sources, The data for one bullet, such as a 230 gr. FMJ in .45acp could have been obtained using several different bullets, with several different seating depths. But since they don't give all that information you're on your own, but I'm sure they have lowered their max loads enough to keep themselves from getting sued.
Their manual, in my own opinion of course, is just like every other product they market. It's not quite as good as most, but it is a lot cheaper. Don't misunderstand me now, I have editions 1 and 2, and if there is ever a third I'll probably own one of those too. But they are only used as a back up reference, or in case someone has a question about Lees powder handling equipment. I do not load directly from them if I can help it.