There isn't a universal agreement on when to start counting "weeks".

Some people start counting when they plant the seed/cut the clone. Some start when they sprout. Some start with the first set of true leaves or at a certain number of nodes.

The chart says to do 1ml/L for seedlings and clones, 2ml/L for small plants, and 4ml/L for mature plants so adjust accordingly.

That's a minor burn IMO. If it were me I'd drop to probably 3ml/L, 2 if I wanted to play it extra safe. Your plants are good sized, they're not really small.