I'll forgo the temptation to suggest that Roche's PR's omissions and elisions would provoke indignant 'Scam!' denunciations if our favorite little company had made them, in favor of sticking to the temporarily more interesting business of the day.
Your interpretation of the PR's obscurities re the 78 and 90 per cent thresholds looks convincing and solves the puzzle. Presumably the protection of the minority holders is satisfied this way? Was a simple majority of the minority all that was required under the original Roche 56% acquisition arrangement? There are no other protections under law, right?
This remains a fascinating situation. There's only one strategic buyer for the DNA 44%: Roche. But the minority holders can choose not to sell, presumably a bet on DNA's earnings growth boosting the stock. Yet ultimately, how does the value from any such growth get to the minority shareholder? DNA does not pay dividends. Could Roche block them from doing so in future? Is / was DNA ever worth more than what Frans Humer or his successor decides? Have I been reading too much Le Carre?