Announcing The Exchange Server 2019 Sizing Calculator

The calculator is driving me crazy. Something is way off. Example:

Download a fresh version of Calculator 10.5

Set "Total Numer of Tier-1 User Mailbox": 1000

Set "Total Send/Receive Capability / Mailbox / Day": 50 messages

Set "Initial Mailbox Size (MB)": 500

Set: "Mailbox Size Limit (MB)": 1000

Role Requirements tab now shows: 610 mailboxes / database and 16 databases. This is 9.760 mailboxes. How is this possible when "Projected Mailbox Number Growth Percentage" is set to 0%?

"User Mailbox Size" is calculated to 1317 MB, which makes sense. But the "Volume Requirements" tab shows 16 databases with a size of 785 GB. A total of +12 TB due to the miscalculation of mailboxes / database. This makes no sense to me and makes it impossible to use the calculator.

I have tested this on two different machines with the latest 365 Excel and an old Excel 2010 version as well. What am I missing?