I paid equivalent of US$1.2 k to have the same done for my Hasselblad sensor. - looked like the glass suffered something the dull patch visible in the pic has a matte surface. And it shows up in the photograph. I had to have it replaced twice. Fortunately my dealer fought for me so I paid only once, as Hasselblad had wanted to charge me another $1.2k after the replacement had the same problem after 6 months.
For comparison purposes, my dealer said that Phase One quoted $1650 just for cleaning of my sensor cover glass of my ex IQ250 after trading it in due to some visible mold/corrosion/something on the sensor side of the glass. I never saw the actual quote so it is possible they were replacing the glass and my dealer misspoke. Luckily I was not on the hook for it.
Glad it is getting repaired, and at a fairly reasonable cost!