FlightPathOBN:
You're mixing PANS-OPS and TERPS. The MSA at UIII is PANS-OPS.
The illustration you show is a DME ARC from TERPs with 1,000 feet of ROC, because it is an initial approach segment. Nothing is stated about Designated Mountainous Areas.
You obviously don't work with U.S. TERPs or you would know that initial approach segments are a minimum of 1,000 feet ROC; DMA or not.
Feeder routes are de facto airways with a minimum ROC of 1,000; 2,000 in DMAs.
MSAs are always 1,000 feet im the U.S., because they are not operational altitudes.