Are we doing anything wrong ?
In my opinion, only one thing.
We do everything you do, then, once we've finished the clean we go back to the first window and start again, doing glass only. In winter, we'll give it five minutes before going back to the start.
The purpose is to let any runs do their worst then go back and clean off the dirty water they have brought with them.
It might sound like it'll add a lot of time, but it's glass only and quite quick.
Try it - it'll transform your first cleans.
Vin