Excuse my ignorance, but I haven't been following this too well. What precisely are your definitions of SALT and MSA?
For example, someone said MSA only goes out to 25nm - that's not so, although the sectorised MSA shown on TAPs does. Apart from the 4nm buffer, that is. But a route can have an MSA, too. And the "contour envelopes on Aerad charts are MSAs, too, aren't they?
I must have known this once, but it seems to have gone...
This relates to another thread on the Flight Deck Forum. Someone was asking about En Route Safety Altitudes, Sector Safe Altitudes, and now JAR has "Minimum Flight Altitudes". I think we're all in danger of getting confused over something quite important.