[snorkelbill]

I'm way younger than you guys, but I can chime in on a couple of the points. You for certain gain advantage for every dev point you put into END, regardless whether it increases your actual END score. I verified this the last time I bumped my end up. I did a bunch of trains, got my average, then pushed end up to just before leveling it up. My average went up by about 2% per train or so. Then I pushed my END up to the next level, and my trains stayed around the same as just before I bumped it.

I also remember reading way back when I first started playing that someone (probably Zeon) said each END point was worth about a 2% gain on trains. I've actually never tested that theory out with hard numbers, but from observation, it's about right.

I know people who have way higher END have said that at some point the gains are completely off that scale, but I don't remember when that break happens.