For comparison, the German version cost millions, too. That included multi-language support, setting up help lines, security evaluation, load testing millions of concurrent users and, IIRC, connecting to quite a few of different hospital computer systems.
Add in time pressure, and costs go up. Germany did get a quality system, judging by what the spokesman for the Chaos Computer Club said (paraphrasing: ‘we have the unfamiliar problem that there is so little to complain about’. They never endorse stuff, so that’s about as endorsing as their statements can get)
And just in salaries, not including payroll taxes, office space, admins, QAs, etc.
850k sounds eminently reasonable for such an undertaking in such a short period of time.