What is the difference between the John Deere 1023E and 1E 23?

Here is how the John Deere 1023E and John Deere 1E 23 compare on John Deere's published specifications:

• Horsepower: John Deere 1023E 21 hp vs John Deere 1E 23 22 hp
• Fuel capacity: John Deere 1023E 6.3 gal. vs John Deere 1E 23 5.6 gal.