The thing that reeeeally annoys me about growth charts is this.
They are based on American children.
Formula Fed.
In the 1970's.

That's where the data for the growth charts that we use today came from.

The WHO has published revised percentile charts recently that reflect the growth curve for breastfed children:
WHO | Weight-for-age

Even if your bub is not breastfed these charts are still more reflective of normal weight gain than the ones that are in your baby health record book.

That said I hate growth charts and I don't even know how much either of my kids weigh They're happy and active and engage with me and their dad so I'm happy