Upon checking here I found that you request a billing cycle change on the middle of the cycle for X/X - X/X. And for that billing cycle the generated balance for your previous cycle is for X/X - X/X charges only.
And for the current bill the remaining charges for the previous bill has a pro rated to the current bill so that's why your current bill is high confirm to the previous bill. The $XXX is for the current and previous bill combined. You can expect that your bills moving forward will be at around $XXX approximately.
In a few words, your previous bill is for a shorter days of service compare to your current bill. If you have further questions or clarifications regarding this, please let me know.