You are right in your analysis. What is clear is that we would be reluctant to launch a DAF that is too small in size because of some fixed cost. Below 5000 k ETH it might not make a lot of sense. So in theory we would launch a DAF even if we do not reach the 20k ETH mark to do so. If for example, we raise 30k ETH above the 40k ETH target, it is very likely that we would launch 2 DAFs with 15k ETH each. With regards to DAFs that are launch with external money, we would not want to go below this 20kETH because you might have additonal costs as they will pull money from investors and for security and transparency reasons, we might have to implement a specific structuring to make everyone happy and safe.
As promoter of this project, our interest is in launching the first DAFs asap in order to initiate this long series of DAFs that will generate money for all of us.