Going Up/Down in percentage

Hi there dear drinking community! I have a question about alcohol percentage. I’ve always heard that when you drink you should never go down in %, always go up. For example, you should start your night with beer (around 5%) then gradually make your way up until you reach those hard liquors like vodka/tequila/whiskey (around 40%).

I’ve always been warned to “never go down in %” but I can’t find a logical scientific answer as to why. Am I dealing with a drinking myth here??