Yes, you never want to use the stabilizer jacks for leveling. On a travel trailer they are just for stabilizing.
There is a procedure for getting the best scale weights.
Forest River Forums - Downloads - How To Weigh | CAT Scale
That's the link from the library page but, if you go through the library there are also alot of other helpful resources there too.
That will tell you alot and it will help ensure you have your hitch setup the best.
By the way, what brand hitch do you have? What are the weights of the bars? Is it a chain type? Does it have sway control?