Example: If you combine a level 4 formula and a level 5 formula, the extract slot you have to use for the combination is a level 7 or higher slot (two higher than the highest level formula).
Edit: Technically, by that text the combination's actual level would be 7 as well, not just the slot it filled. That should affect DCs and the like.
So to be clear on this, if you have access to extract
Levels 1-4. You can only combine extract to a max level of 2 as you need to use the 4th level slot which is 3 levels higher? You couldn’t combine a third level one as you don’t have access to 5th level extracts?Also combining extracts only uses one extract slot but from two levels higher?