Sounds like a good plan!
And remember, this is the age where babies tend to become more active, lean out somewhat, and slow their weight gain, while continuing to grow in height.
Anecdotally, I have a friend whose son was a very rapid gainer. (Fed EBM only from a bottle...long story) Anyway, he was HUGE by 4 months, like 25 pounds if I remember correctly. Do you know how much he weighed at a year? You got it...25 pounds! But he was much longer, and therefore leaner. He was walking by then.
So, just a little story I like to sometimes share when discussing weight gain in the second half of baby's life.
Good news about the tests!