Nope, I've never seen Microsoft shared such plans.
If you are on Monthly Targeted (former Insides Slow) from Office 365 administration point of view you shall be able to install Insider Fast as well. Installation itself is quite straightforward.
Main issue, especially in corporate environment, is compatibility if you fully shift on Insider Fast. As for me, I'm also on E3 and Monthly Targeted on my main Win10 corporate PC. On that same PC I installed Hyper-V virtual machine with Insider Fast office. Here are some administrative rights and licensing issues, but in general everything is solvable.