Audits are typically revealed, and you are either checking to see if things are as they should be or you are certifying something. Half my shops are audits.
Merchandising is when you actually put the stuff up for a particular company, usually on a special display (think of the cardboard stands in Walmart). So are terrifically easy, but beware. I once did a four hour turned into 8 hours because I didn't have the information I needed shop, and it was bad. I do not do merchandising, it is more physical than mental and like putting together a puzzle with one tenth the pieces missing.