Thanks for comments. I will redo the experiment with the water bath filled as full as it can be filled.
I have had inconsistent results with C41, with the same films developed in different runs needing different filtrations when enlarging. Some runs have been OK, but none have been as good as the negatives I get from a commercial lab. Those have better contrast and higher density than any film I developed myself and I can use the same filtration for each and every film (of the same type) when enlarging. The film base color is always lighter in the negatives I have developed myself than that of those developed in a commercial lab.