Not really wishing to cover old ground or be too pedantic regarding tantalising snippets about were and when 558 would or would not appear surley anyone with a grain of sense must understand the phrase 'Subject Too Servicability'.
558 is currently not servicable simple as that, when it is then the groups calender will advertise the dates that it 'May' appear and when they do I am certain that everyone involved will do there best to ensure those dates are kept.
So in the absence of a fixed date for first flight we must all rely on the engineers having the time too update the website or answer questions on the TVOC Forum with regard too how things are progressing.
Beyond that speculation is a rather futile occupation.