AVERAGE not showing the same result

Hello All,

New to the forum and wondering if someone can explain a problem for me please.

I have 13 cells that i need to average. When i took on the worksheet, it had a formula using SUM to get the AVERAGE. I changed it to show the proper formula AVERAGE but it came out with a different result.

=SUM($E8,$G8,$I8,$K8,$M8,$O8,$Q8,$S8,$U8,$W8,$Y8,$AA8,$AC8)/13 - (result = 60.7%)

=AVERAGE($E8,$G8,$I8,$K8,$M8,$O8,$Q8,$S8,$U8,$W8,$Y8,$AA8,$AC8) - (result = 65.8%)

Am i using AVERAGE wrong? Do they function differently? Please explain the difference.

Thank you!