We have a horse that was the same way on oats! I found out oats are about 44% sugar and starch! Thus the boucing off the walls!
A low starch, high fat feed would definately be the best route for you....you can provide lots of calories from fat, without getting all the carbs that hype them up!
My personal favorite is Tribute Kalm Ultra. It is a lower starch, high fat, high fiber product. I LOVE IT! I've got all my harder keepers and show horses on it!
Safe Choice and Strategy are both "least cost" formulas, meaning they are subject to change from batch to batch. If you look at the ingreidents there are things like "grain products," "grain by-products," etc. listed, which means they can change the ingredients to keep the costs down. Also, there are actually 3 different forms of Safe Choice on the market right now....I have all 3 tags....AND they added corn to it, so its not nearly as low in starch as it used to be.....just fyi!