Hold it there. You are saying that they said that no one was at home. That is quite different from what the record states. You have to be able to understand the legal jargon though.
According to court records, prosecutors reduced the charge to second-degree burglary because they couldn't prove that Johnson had been home during the theft. "It was, in effect, a stipulation by the state that the house was not actually occupied at the time," states a 1971 state Supreme Court ruling rejecting Allen's appeal.
The "in effect" is very important. In reality, the prosecution said no such thing. They only said they couldn't prove in court that the house was occupied. This is not the same thing as what you said. Not being able to prove something is, is quite different from saying that something is not. Although in the trial portion of a case it can have the same effect. If you can't prove it, you can't bring it up.
The sentencing rules though are a bit less ridged. The judge may consider things that were not brought up in the trial portion. Sentences are generally made harsher or more merciful depending on what mitigating factors are brought up at that point.