Drinking Chart Help please!

Please no judging. It is my husbands birthday and we have decided to go out for a few hours and have some drinks. I have pumped 3 bottles worth I think 😐 I have 12 oz for him anyways hopefully he doesn't need more then that because I haven't bottle fed him breast milk since the first of December so I'm not sure exactly what his intake is he is 3 1/2 months. Anyways what I'm wondering is on the chart it says when you have this many drinks wait this many hours and to start counting when you start drinking but would I have to drink them all in one hour for it to be valid ? I'm so confused or can I have them over a couple hours and still start counting from the first drink. Any advice would be greatly appreciated 😊