Silver Line Windows by Andersen / Ply gem

I work for a contractor regularly doing CCU and he always uses Silver Line windows who are now made by Ply Gem I found out rather than Andersen.
I finished a CCU yesterday and when the sun was getting low in the sky it showed so many marks and seemingly unclean spots on the windows but I was completely unable to get them to come off. I mop them and go back over with invisible glass and an Unger Pad to catch all streaks but it seems like I can never make these look spotless after many passes. I noticed that they have a lot of dirty spots in almost every one of their windows on the interior of the dual panes where they must not have got them spotless before putting the window together at the manufacturer.
Does anyone find that being the case on a regular basis? Is Ply Gem a Sub Par company or is this fairly normal?
The contractor has never complained about my work but man it’s super difficult to determine when to leave the job even though it still looks like there are spots on windows.

Sorry, not familiar, but I would be surprised because Anderson makes some really nice windows, at least from what I’ve seen.

Sounds frustrating. If it’s in between the glass panes then can’t do anything about it, right?

Seen that before - the installers are supposed to wear gloves - it is annoying. You need to show the contractor if the marks are between panes, customers sometimes can’t tell outside from inside glass so between the panes is beyond their experience. If he’s not there in person send him a video where two people are applicating and squeegeeing a bad spot from inside and outside to get the point across.