Series is not 'official' DC metadata.
Like many, I also massage my metadata and covers upon import. For most part, downloaded metadata is a jumbled mess.
Some of this is because INDIVIDUALS provide many sites
with their version .
Toss in Publisher (we are talkin' at you larger houses) inconsistencies (even their own NAME

)
Then the Authors change their mind as the series progresses.
So the simple answer: Do it your way!

After all, it is YOUR library