I used a Gold 3 Tiered Medallion Setting on my crafted necklace and only received the ability to add 2 sockets to the necklace when the description says that quality should allow me to add 3 sockets.
You need to use 1 of each.
The R1 will give you a first socket, then you use an R2 to give you the second socket and finally, you use the R3 to give you a third socket.
The quality of the Setting only determines up to which socket # (first, second, or third) it can add; it does not improve the number of sockets added.
Hmm okay so question. The item is the torc of passed time neck for my hunter. It comes with a socket spot, then I used the R3 Medallion on it. So what you are saying is I should use a R1 and R2 medallion now on it as well to get more socket slots?
Your cheapest option is generally going to be to use two r2 tier medallions first for your first two sockets, then use a r3 for your third. You must always use 3 medallions if you want 3 sockets.
Ok so now that I have 2 sockets on it already I need to use another R3 medallion to get the last one?
Yes. Since your item already had a socket spot, you needed to use a r2 for your 2nd socket, and then a r3 for your 3rd socket.
A rank 1 medallion setting can allow 1 socket, a rank 2 will allow 2 sockets, and the rank 3 allows 3 sockets. These are total, not additional sockets. Since the torc comes with a socket by default, you can only add 2 additional sockets and it must be done via a tier 2 + 3 medallion setting or 2 tier 3 settings.