vegetable oil vs soybean oil

my feed rep at the local mill recommemded using soybean oil to more cover on calves and help with hair coat.  but after doing some research on here found people usinf vegetable oil as well.  anybody have some pros vs con on both.  also can it be used vegetable oil ( i trust the store  were i can get it at.) or need to be new oil.
thanks 

also what would be a good amount to mix inro feed of each

I could always buy vegetable or corn oil on sale at the grocery store cheaper than the feed grade soybean oil (less than $10/gal. of cooking oil vs $54/5 gal bucket for soybean oil).  Also, soybean oil seems to have a stronger smell and flavor, but maybe it was just sitting around too long and getting rancid.

I work at a bean crush plant, vegetable oil and soybean oil are the same thing.

How much should i mix in feed.  My feed rep said 2 oz per head per day.  Is this sufficent