Mike, here is a FIRST plot from Vandalia, IL, not sure if it is your soil type but it is closer to you than a lot of plots. 5828AM was in the top 3.  The top 5 were significantly higher than the test average yield.

The trouble with plots is it gives numbers which we then quantify and calculate and rate and make a big thing out of, trying to make them more important than they are.  The FIRST plots are supposed to be pretty good. I think they are replicated and maintained and about as good as can be expected.  I've seen too many over the years that were at best worthless and often mis-leading.  I remember one plot I did very well in because I was in just the right place in the field.  The county extension plot was planted on the side of a hill to show conservation practices as well.  If you got in the right spot you had good drainage and good dirt.  If you were in the wrong spot you got the yellow stuff they pushed around and all the water pooled in your plot until it drained off down the tile system.  Try and understand a plot before paying too much attention to it.

Getting back to this plot, I didn't have the chance to take statistics in school, but my understanding is the LSD(.10) and LSD(.25) numbers indicates how much of a difference in yield it takes to be significant. If I understand that correctly it means statistically the top 11 hybrids were close enough to the high yield to be considered the same, even though there was about a 15 1/2 bushel difference in yield.  Maybe someone who understands statistics better than I do can explain all that.