We are getting a little caught up in the details here and forgetting that the most specific addresses are all to Harry in Sorcerers stone.
Yet here it was, a letter, addressed so plainly there could be no mistake:
Mr H. Potter
The Cupboard under the Stairs
4 Privet Drive
Little Whinging
Surrey
Later
She held up a letter so they could read the green ink address:
Mr H. Potter
Room 17
Railview Hotel
Cokeworth
These letters are the exception, and not the rule. Do not forget Hagrid was actively sending these letters to Harry, and physically following the Dursleys around the country side. He always knew exactly where Harry was.
"I was allowed ter do a bit (magic) ter follow yeh an'get yer letters to yeh an' stuff -- one o' the reasons I was so keen ter take on the job --"
Every other instance of letters we see are either sent broadly with owls to just the recipient, maybe including their street address.
Why were Harry's Hogwarts Acceptance Letters Not Sent Directly To Him? review my answer to this for details.
The only other exception i know is the letter from Percy to Ron. But that letter was meant to be received in the gryffendor common room, not in the morning owl post.
Do owls deliver only in fixed daily windows? review my answer here for further details.
Ron, I want to give you some advice, which is why I am sending this at night rather than by the usual morning post. Hopefully, you will be able 'o read this away from prying eyes and avoid awkward questions.
So other then the letters addressed specifically to Harry in book 1, we only see vague letters with recipients names, and potentially address, and in very rare cases the owls were to deliver to specific rooms at specific times.
Harry also states that at least for Hedwig address's are not important.
Harry’s owl had never yet failed to deliver a letter to any- one, even without an address.
