If you are Bozo University that has no grants, you also have no overhead, because everything you spend is attributable to that first grant. You spend $50 for tiny little flasks of liquid nitrogen. You buy paper at Staples.
If you are UCSF, you have 80% "overhead" because everything is centralized. Your LN2 is delivered by barge. You buy paper from International Paper, net 20, by the cubic meter. You have a central office that washes all the glassware. Your mouse experiments share veterinarians. All of this costs much, much less because of the "overhead".
If you are Bozo University that has no grants, you also have no overhead, because everything you spend is attributable to that first grant. You spend $50 for tiny little flasks of liquid nitrogen. You buy paper at Staples.
If you are UCSF, you have 80% "overhead" because everything is centralized. Your LN2 is delivered by barge. You buy paper from International Paper, net 20, by the cubic meter. You have a central office that washes all the glassware. Your mouse experiments share veterinarians. All of this costs much, much less because of the "overhead".