The final agreement is set out in an amended Article I-24. To say that the procedure is mind-bogglingly complex is something of an understatement. The text actually does not make sense but, as far as I can work out, there are two stages:
Firstly, a qualified majority shall be defined as at least 55 percent of the members of the Council.
However, the majority must comprise at least fifteen member states which must collectively comprise at least 65 percent of the population of the Union (which is actually 60 percent of the member states).
Then, the "blocking minority" must include at least four Council members.
Only if all three hurdles are surmounted are the conditions satisfied.
However, just in case you thought you understood it, when the Council is not acting on a proposal from the Commission or from the Union Minister for Foreign Affairs, the qualified majority is 72 percent of the members of the Council, representing Member States comprising at least 65 percent of the population of the Union.
Then, there are separate cases, where only some Council members have the right to vote, such as with enhanced cooperation or Eurozone.
In these cases, the percentages are applicable only to Council members which have the right to vote and to the population of the Member States which they represent. The blocking minority will be "the minimum number capable of constituting a blocking minority through the population criterion plus one".
If anybody understand all this, perhaps they would be kind enough to explain it to me.