Im leaving tomorrow to drive to Fort Worth, TX from Southwest GA. Last time I went I-10 to Mobile, Then Mobile to Hattiesburg, Hattiesburg to Jackson where I get on I-20 for the rest of the trip. It took me about 13 hours last time.

Looking at a map, though, it seems it would be better to go I-10 to Lafayette, LA then
I-49 to Shreveport, then get on I-20 in Shreveport.

To me, it seems like it would be quicker to go this way because it is entirely Interstate, as opposed to the Highway in between Mobile and Jackson. However, my GPS says it would 30 minutes longer. Anyone have any suggestions as to the best route?