The problem is in the schedules.
You may have identical doors/windows and when you 'merge uniform items' they will merge into one entry and you can get a count of the total number (quantity) of those items.
But as soon as you add unique data and try to schedule that (ID for example), then the item become unique and will all schedule separately.
In your case, so long as the doors are all identical and have exactly the same ID, then you should be able to schedule the orientation (handing) and you should end up with 2 entries (left and right) for which you can get the quantity of each.
It is not possible to show a single entry of 5 doors unless you take out the orientation - which defeats the purpose of what you want.
Every filed you introduce will create a unique set of information.
Every unique bit of information will create a new entry in the schedule.
There are wishes for this already.
At the moment I can only find this very old one where they want to list similar door as one item and list all the unique IDs in one entry.
This can only be done at the moment with a custom text field and manual entry of the IDs.
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