There already are enough threads discussing "likely" tank level past MTE, so I won't belabor it here... but 100 miles & .75gals left?!? Man, that's amazing! At ~40mpg, that's way beyond the assumed "consensus" of 2-3 gallons so far.

I haven't dared risking it beyond 30mi, and have no need for it based on my commutes. I do like to go beyond MTE each & every time, though, just to see if my cruising range will ever make it to 600 (and nash: hush! I don't want to hear or see your picture again! Re: For fun: most miles on one tank of gas? -- just kidding: it looks great!)

Anyway, to get back to the main point of this thread: Ian -- yes, a sudden drop seems common but I have yet to see such a drastic jump (or "fall"): mine have been more in the teens. As everyones knows, it not only depends on sudden acceleration but road angle as well (i.e. going "up:" or "down")... and once it marks 0 MTE, it doesn't come back up again -- although I have had two occasions where the needle got out of E and climbed back "up" for ~5 more miles, but MTE remaining at 0. Go figure.