After thinking long and hard... No you don't have to recal the battery... you have to just get a new battery!
I am not quite sure where the problem lies... now you did a verbatim from beginning to end reflash ...up to turbo with asui ... and did it with no issues along the way.. ...right?
The root culprit could be a variety of things... including needing to reset the batt charge indicator to express the current charge...rather than an echo...or delayed reading.. I know in the last 3-4 years I saw a thread about doing it on the n8x0 ...somewhere in the subforums... Just can't remember where...