What NordeastBrewer77 said so eloquently said could also be described said is a couple of sentences. Such as:
Don't worry about what the recipe says for yeast, go off the science of it, calculate how much yeast you need and pitch that amount. Under pitching = too many esters and the possibility of stuck brews (high FG), high fusel alcohols and increased risk of infection.
Over pitching results in reduced esters as required by style, generally accepted as less of a problem and usually only done by home brewers when they pitch directly on to a yeast cake from a previous brew. Otherwise a non-issue.
Many recipes (not on this site so much but rather one at homebrew shops) say hydrate a packet of yeast and pitch.... hmmm they could sell more stuff if they encourage correct pitching rates, I still don't know why they don't push that angle. I would only pay attention to a recipe's recommendation about yeast pitch rates if it said something like, "attempting to get an increased ester profile so intentionally pitch 80% of ideal pitch rate".
Clem