That math ain't mathing. Every single one of your assumptions is assuming a lot, and when you assume you make an ass of (yo)u and me. If your result is an order of magnitude greater than the data you're trying to explain, you have made some fundamentally incorrect assumptions. When it comes to data, trying to explain something and getting a much higher result is a sign that a major mistake was made- if you estimate why something is happening and get a low number, it's possible there are other sources inflating the number, but if you try to estimate why something is happening and get a higher number, unless your data is wrong, you are misinterpreting it badly.
DDO audit is looking at the number of characters online, not unique logins. It also isn't capturing logins at all- Someone could log in, AFK in town for a half hour while grouping or doing other things, run a quest for 45 minutes, and then hop off, and that's captured the same as someone who happens to be fingerprinted just logging in for daily dice or someone AFKing overnight because they fell asleep with the game running.
Also, DDO tends to take a significant amount of time to run a quest- sure, some quests are five minute romps but if you're running, say, Lamordia, you might be online for a couple hours to clear a chunk of the quests.
There's also some fundamental errors in your assumption around logins and character numbers, even if the time snapshotting gets ignored. If someone logs out and logs back in they are still the same person. Do you make a new character every time you play DDO? If not, then I have no idea why you're guessing that these logins reflect unique characters.
With transfers all the numbers are going to be different. Though 688,400 unique characters logged in the last three months, that is going to be extremely different than normal- some of those characters likely hadn't been touched in literally years (I know that's the case for some of mine). In a more ordinary time, that number of unique characters is likely to be significantly lower.
This is a classic case of seeing data, conflating data, and being extremely wrong about what it means. Online player counts *DO NOT* capture the uniqueness of the users/characters involved. During the transfer process, I probably spent less than an hour logging in to about a dozen characters on one server. According to your first data point, that whole time I would look like a one the whole time (unless I was on the select screen), and to the second I would incrementally increase every time I switched characters, because one character was online for the time stamp population audit but the second one would tally up over and over again.
Let's look at a hypothetical (and not an assumption- I am not trying to explain the numbers, just do some napkin math to try to establish what might be happening) that the player base has, lets say 3000 daily active players (which is low- peaks are usually about 2700 and not everyone is online at the peaks) representing a conjectural 10000 weekly active and 20000 monthly active players. If each of those 20000 active players is transferring a couple characters and checking some more (let's say five total on the 32-bit worlds), that would easily be 100,000 characters logged into in a month at a conservative estimate of five characters being logged into per account during the transfer window. Now, depending on how DDO audit tracks characters, it probably also counts pre and post transfer characters as the same, so if each monthly active player transfers three characters that's another 60,000 since Character1 on a 32-bit world and Character1 on a 64-bit world probably look unique to DDO audit. Count in also people who only logged into DDO to transfer, but didn't play, because they wanted to move their characters but aren't actively playing and those numbers might be significantly higher.
That gets us much closer (still very short of the actual number but I did do a very conservative estimate, since while a lot of people might just have a main there are others who I know have dozens of characters, sometimes on multiple worlds) without even accounting for people actually playing the games, making alts on the new servers, etc. Without knowing how DDO Audit actually tracks unique characters, then this feels like a much more accurate way of interpreting and understanding the data- transfers mean people are logging into all their characters instead of just their mains- still a very rough "math ain't mathing" estimate but without having to make assumptions correlating active player counts to unique logins which are not mutually supporting datapoints and instead looking at events we know happened and can measure behavior from, and I didn't have to make up numbers to reach my conclusion other than guessing at monthly active player counts using daily active player counts (which admittedly is very rough and not reliable).
