ya, that’s normal.
As you gain rep, you’ll be able to put more points into salvage, which will give you more salvage shares. Also, multiple-part missions help a lot with this (though they’re probably too hard for you right now). You’ll see some missions will offer +25 -75% bonus shares (and that applies to each stage of the mission, so it can be quite lucrative). At the beginning, you’re probably better off just getting as much money as possible, but at some point, its more lucrative to go with salvage. Also, in general, i think the campaigns have better quality salvage than the generic, so i’d recommend focusing on salvage for them more than the random missions (this is especially true of the dlc).