Another max req7 question

Yeah, I titled it that because I know there's a million of these, and for whatever reason search isn't working for me.

Basically my questions are:
(1) Does a white +11 Energy/req 6 focus drop tell us anything at all about the existence of max req7's?
(2) Is there some reason it could drop white but not blue/purple/gold?
(3) Does the maximum differential between stats and requirement change between max and non-max equipment?

In case you haven't figured out why I'm asking, I got said focus yesterday doing The Battle for Lion's Arch in normal mode, and I've been thinking about it since. I attached a screenshot of it lying on the ground assigned to me - the chat doesn't show the drop because I was too busy trying to solo monk to be thinking clearly about things like this. Also, the screenshot is kinda embarrassing because the person I ran it with used a conset for normal mode, but whatever - I'm willing to look awful for some answers.

Thanks in advance to anybody who actually knows and isn't just speculating - I can do that part myself (EDIT: upon rereading, this sentence seems kinda rude - I welcome thoughtful speculation)

Offhands have been known to drop with 11e/r6 stats for a while. I happen to have an inscribable version of the one you posted as well.

In short, it has nothing to do with the chances of getting a 12e/r7 one; next in line is 12e/r8 as far as offhand drops are concerned.

So the answers would be
1) nothing
2) can drop blue/purple/gold
3) yes

I'm not sure I understand why there can be a differential of 5 for +11e but only 4 for +12e. I also don't really understand why it's different for foci than other equipment (for example, 8 is the differential for both max and non-max shields) - regardless, I appreciate the information!