First up, you are doing a great job.

Secondly I don't personally believe you can overfeed a formula fed baby, mine have always stopped when they are full. I'd make her a bit more, the tin is just a guide not the rule. My ds was always above the recommended amount but fed every 4 hours, dd1 fed under the amount but fed every 2 hours.

Just demand feed her and don't worry about what the tin says cos the author hasn't met your baby