Education

What the school publishes really doesn't hold any weight with the IRS. Most folks for get the utilities costs of "room" and even more ignore the food costs included in "board". Room and Board is basically the cost of rent, utilities and food. But there are some rules on the maximum amount that can be claimed when the student is living off campus. I'll discuss "room" and "board" costs separately.

Room - What it costs for rent, utilities and routine maintenance (to include yard care if the tenant is responsible for that.) Now if the school offers on-campus housing then what you claim for off-campus "room" expenses can't exceed what it would cost for the student to live on campus.

Generally, the cost for on-campus housing (dormitory style if the student is not married) covers the actual room they live in, utilities (water, electric, internet, gas, etc) and maintenance such as the common areas of the dormitory.  So if the "student" chooses to live off-campus then you can not claim the amount for the "room" part of room & board in excess of what it would cost to live on campus.

Additionally, if the student is living off-campus say, for the summer months and is not enrolled in classes for those months, then the costs being paid for that off campus housing is not "in direct support" of the education and is therefore not deductible at all for those months.

Now if it's a case of the school not having any available on-campus housing and the student has no choice but to rent and live off-campus, the school will provide a letter indicating that on campus housing is not available and the student has no choice but to live off-campus. With that letter you are not limited to claiming only up to the amount it would costs to live on campus. But the amount paid does have to be reasonable. So you can't go out and rent a $5000/mo penthouse suite for a college student and expect the IRS to not notice such a claim.

Now for the "board" portion of room and board. Most colleges offer a meal plan geared mostly towards those living on campus in the dorms. There are different types of meal plans too, each with a different cost. For example, there's the "every day" meal plan that covers 3 meals a day, 7 days a week for the entire semester. This is usually the most expensive and are for students who are away from home and can't exactly go home every weekend. Such plans usually include some extras such as "flex bucks" that can be used to purchase food at on-campus facilities. For example, if the student doesn't feel like going to the dining hall one night, they can use their flex bucks to order pizza from the on-campus Pizza Hut and have it delivered to their dorm.

Then you have meal plans that may only include 3 meals a day for 5 days of the week. These are usually the best for a student who can and does go home on the weekends.

Then you have meal plans that may only provide one meal a day, 5 days a week. This type of plan is geared for s student who lives in the local area and basically goes home (to mom and dad's house) every day. They only need one meal a day so they can eat lunch at school (just like in grade school) and not have to make the lunchtime trip home every day.

So when living off-campus by the student's choice, the amount claimed for the "board" part of room and board can not exceed the costs of the meal plan for that semester that would be purchased by the student if they were living on campus. But again, if the student has a letter indicating on campus housing isn't available for that semester, those limits don't matter so long as the cost is reasonable. So no steak and lobster for lunch and dinner every day. That's just not gonna fly.

Pub 970 uses “room and board” as a collective figure

yes it does, because they are added together and included as one figure on the tax return. But remember, the costs must be realistic and unless you have a letter indicating that on campus housing isn't available, what you claim against the 529 funds can't exceed the cost of room for on campus housing, and the cost of food for a school provided/sponsored food plan.

Finally to reiterate what I've said above, in order to claim room and board costs, those costs must have been incurred "in direct support" of the education. So if the student was not enrolled in classes for the summer months, then not one single penny of room and board costs for those months can be claimed against the 529 funds.