I think it all depends on which brush you are using. 
I used a Salmon with fan jets, rinsed on. 
I loved it but it still left spots some of the time.Never had a  complaint though or lost a customer and used it for at least 3 months. 
Been using Gardiners Supalite mono dual trim for about 4 months, always rinse on, perfect, but it takes longer as only 2 pencils.  Next brush I get will be the same again but either a custom made 4 pencil or fans.