No, as I wrote before, each process has exactly one tag that starts with "Sector: ...". If you add up all tags called "Sector: ..." you will get exactly the total impact result.
Do not add up "coal power" or "hard coal power", since these are the default tags from ecoinvent which might lead to double counting and which might be not maintained or confusing. Better use only the tags starting with "Sector: ..." that we have added from the sector names for processes from ecoinvent.