It seems @bumbak has opened the thread on the HotStart forum, so let's see how that goes.
Doesn't LittleNavMap do that, in a certain way? Not perfect, but it's their way of creating aircraft performance data.
SimBrief aircraft performance data isn't always perfect and they have acknowledge that in the past. Though I'm sure that with the Navigraph integration, that's an area where they can vastly improve.