I'm with the same problem! My girl will be 11 months in a few days. Her tolerance raised from 180-200 mg/day in her 6th month to 230-250 mg in her 8th month. When we were expencting higher tolerance and more normal food for her, her phe was up to 7 continuously a month ago. Now we have adjusted to 180mg, 50mg less! Our doctors said it happens on some babies that tolerance gets lower sometimes in their growth.
It's said the artificial enzyme for CPKU will come out in a couple of years…So, just give a little faith…..