This stuff is really tough to nail down. I finally found some in the 4.5 lb. jug listed on Sears marketplace of all places and quickly ordered it. I only ordered one thinking it might not be the right stuff but when the correct jug actually showed up today I went to order another and they were gone. This should last me forever, though.
I found my Osmocote Plus 4.5lb on e-b-a-y like 3 weeks ago, guy was auctioning it off starting at $16.99 + $13 shipping. So I put a max bid of $25 on it, but surprisingly no one else placed a bid, sat there for 4 days watching it to make sure. I now have somewhere around 1,000 root tabs made up so far, and still have around half of the 4.5lb container still.
Osmocote Pro doesn't contain all of the micro nutrients that Osmocote Plus does, depending on which Osmocote Pro some have magnesium, some don't, none of them contain Boron, some have Molybdenum, and some don't so because of how each series of Osmocote Pro differs on the nutrients they contain it makes it an unreliable fertilizer in my opinion.