RF, if you're asking why the initial approach altitude is 1900 and not 2800 at SHT, that's because the 25nm MSA to the NW is 1900, and it's logical to have your holding/approach entry altitude equal to or less than the lowest MSA on the chart. If you're approaching from the NW you're going to step down to 1900 to get clear of cloud if possible and conduct a visual approach - and if you're not clear at 1900, it's silly to have to climb 900 feet to conduct the NDB approach. As it's published now, we can step down to 1900 from the NW, and if not visual, manoeuver for a direct entry to the approach at 1900.
Growler is right, LTV is another one where a chunk of the 25 MSA is lower than the 10 MSA, and the slice of the 25 MSA to the W allows you to make a nice direct entry at 3000.
I'll try and find an example. My Jepp amendments just arrived in the mail, damn that's a fat one.
Edit: the Innisfail NDB is probably a reasonable example - approaching from the N, to make a direct entry you'd have to lose 4200 feet by the end of the base turn - maybe a bit steep.