Guys I will be posting 13.8 up on Monday. No functional changes, just some text cleanup. Since releasing 13.7 I have had some questions regarding the multiple server functionality and how you input the number of mailboxes. Currently the calculator states this in Step 2 "Number of Tier-x User Mailboxes / Server". The problem is "/ Server" as that only applies to the single server scenario case. If you have multiple servers, then you want to enter in the total number of mailboxes for the environment. For example, if you want to deploy 5 mailbox servers and have each server house 3000 mailboxes, then you should enter 15000 into that cell instead of 3000.
Sorry for the confusion. For now if you are using 13.7, please follow what I listed above when utilzing the multiple server functionality.