You bet your @rse it makes a difference if the plae is overloaded. Although, in all seriousness we all kow that the meager standard weights used these days I personally think that any flight which is at MTOW on paper is a few hundred k's over. That's my opinion based on what I see entering the cabin sometimes, and the exceptional ability (especially the caribbean region) of passengers to have a 20 inch tall handbag weigh close to 30 pounds. The poor carriage wheels got stuck under the weight loooong ago to the point that they are half circle shaped as they've been scraped down to axle
But those extra kilo's are mostly carried over in the margin of error calculations, but to add 2000 Kilo's of known overweight into the plane will most definitely affect single engine performance.
I wanted to elaborate on the MD-80 thrust settings, but I see that it appears clear to most.