New Charger - Range has increased

This is interesting. I have 5,849 miles on my 4000li. Have owned it for 10 months. Initially, even though the batteries were dated 2008, my 4000li had a range of 47.6 miles on a full charge. Over the miles and months my range dropped, and at around 3800 miles my range was 32 miles. Well my charger burned out, and I received a new one this week. My range after 4 charges with the new charger is now up to 38 miles. I will see how she does over the next several charges, but I have a feeling that range will increase. Has anyone else ever seen this???? (20 Thundersky 40ah cells)