The OP's post has been answered, but just to add a voice to this discussion (to hopefully see it changed in the future) it would be nice if the term was changed to "Qualifying Offer" in that lower section instead of "Offer Arbitration."
If you qualify a seemingly decent player that the game suggests is asking for much less than the qualifying offer that's entirely your fault if the player takes you up on it.
What is sometimes tough is when the player is in the "ballpark" of what the offer would be and the only choice is signing them to multiple years at the ballpark number or qualifying them if you do want them to stay for one more season.
And the real difficulty, in my opinion, is when a player refuses to negotiate all season and says he "wants to test free agency." You would think it's a good idea to qualify them (at any price IF you feel another team might sign them in the off-season) just for the draft pick, because they aren't coming back anyway. Right?
Not so, in many cases!
And some do actually decline, but not many!
The amount of the 1-year offer is, as I recall, identified in the small print in that section on the arb page but it would be nice if it was more clearly spelled out as this comes up often (in the forum and online leagues when the arb period opens).