You have to look at why are they busy at particular times though. Is it first thing? That’ll be breakfast on the way to work. Lunchtime? Speaks for itself. Early evening, that’ll be after work.
People can’t just randomly change their work hours to suit Subway/Wendy etc prices.
And, not everyone wants breakfast at 11 am and lunch at 3pm.
Any company upping their prices because it’s busy are just gouging customers.
How about they reduce prices when less customers are about?