Disclosed herein are systems and methods for allocating fully-orthogonal and quasi-orthogonal spreading codes to access terminals in radio access networks based on a tolerance level for additional interference on a per-access-terminal basis. An embodiment takes the form of a method that includes receiving a request for allocation of a spreading code to an access terminal, and responsively comparing an additional-capacity number to an available-codes number. The additional-capacity number represents, based on an average contribution per access terminal to the current reverse noise, how many additional fully-orthogonal spreading codes could be allocated to access terminals without exceeding a maximum-allowed reverse noise. The available-codes number represents how many fully-orthogonal spreading codes are currently available for allocation. The method further involves allocating a fully-orthogonal spreading code to the access terminal when the additional-capacity number is greater than or equal to the available-codes number, and otherwise allocating a quasi-orthogonal spreading code.