Why are there 2 separate charges on my bill for additional cloud space????

1. How do you know both of them are for iCloud storage? Apple does not specify what the charges are for on your monthly statement. It would only show apple.com/bill.
2. Unless you are the Family Organizer in Family Sharing or are sharing your credit card with someone, there is no way to get charged twice for iCloud. Since you can only activate one iCloud subscription at any given time on your Apple ID. If you are the Family Organizer and as such paying for purchases made by everybody in your Family Group, then someone else may have started an iCloud subscription on their account. You would need to cancel it from there.
3. If you are not part of Family Sharing, and did not share your credit card with any one, then Check your recent purchases to identify the charge. Link-> If you see 'apple.com/bill' on your billing statement - Apple Support

Good to know. Would you care to tell us what the answer was so others that come across this post can benefit form it?