Your negatives will now come out backwards!
If I understand these things correctly, in most cases the reason for mixing things in the order suggested is that some things don't dissolve very well unless you use that order.
Did you later put in the part A, and did it all dissolve?
If I were you, I would contact Ilford/Harman using their contact form on their website and ask the question. You could also "Start a Conversation" here on Photrio with Harman Tech Service and direct them to this thread.