I tend to feed my adults a larger prey item less often, sometimes 7-10 days but sometimes 14 days, it really depends on my schedule. I've never felt that snakes benefit from an exact feeding schedule. Likewise the prey item I feed them depends on when I last fed and what diet the snake is on, I base on weight (sex and situation), never on length. Females get more than males, especially during breeding season before and after laying eggs. One of my males goes 8 weeks of the year during breeding season every single year without touching any food although I still offer it every 2 weeks - he's never lost any weight because of it.
I think regular weigh-ins and knowing your snakes helps a lot for you to make up your own feeding regime. The same adult male specified above is a 5.5 foot ghost corn weighing 700g. He only has a medium to large mouse every week, and he maintains a regular weight, doesn't lose any, doesn't put any on, is active and healthy. Most of my females (breeding) who weigh around the 400-500g mark at 4-5 foot have a large rat weaner that is almost 3x the weight of a large mouse, and this is what keeps their weight steady across the year, obviously after egg laying they do drop a fair bit but tend to put the weight back on within 6 weeks and then remain steady.
I also keep an eye on the digestion, I find that my regime they digest within 24-36 hours. I know some people have told me their corn snake hasn't digested 3 days later, in which case I would consider either smaller meals or rechecking temperatures. Digestion should be nice and regular and predictable. If a snake has a problem digesting a certain size it may not be the best size for them, we all have slightly differnet digestive systems.
All of my adults get between a large mouse and a large rat weaner every 7-14 days (most often averaging 10 days)
Sorry this is a long post to basically say that only you can know what is best for your snake as an adult, it's important to monitor weight, activity levels, digestion, assess if the snake is going to need fat reserves (to support eggs for example) and find a size prey that keeps them steady, happy & healthy.
With growing snakes it is slightly different, as you don't want weight to remain steady, but to increase, but I still think diet should be tailored individually, although the chart looks useful for a rough guide